尊敬的 微信汇率:1円 ≈ 0.046166 元 支付宝汇率:1円 ≈ 0.046257元 [退出登录]
SlideShare a Scribd company logo
© 2003 Prentice-Hall, Inc. Chap 8-1
Basic Business Statistics
(9th
Edition)
Chapter 8
Confidence Interval Estimation
© 2003 Prentice-Hall, Inc.
Chap 8-2
Chapter Topics
 Estimation Process
 Point Estimates
 Interval Estimates
 Confidence Interval Estimation for the Mean
( Known )
 Confidence Interval Estimation for the Mean
( Unknown )
 Confidence Interval Estimation for the Proportion
σ
σ
© 2003 Prentice-Hall, Inc.
Chap 8-3
Examples of where CI are is used
(continued)
CI of Means
1000 Salaries of people in Phnom Penh:
Sample Mean =
How confident are you this is the same as the Population Mean
Salary of the Phnom Pehn? (The average if you had all the data
for every one in Phnom Phen)
Two Methods to work this out: -
1. Confidence Interval Estimation for the Mean ( Known )
You could use the Standard Deviation of men in Cambodia
2. Confidence Interval Estimation for the Mean ( Unknown )
σ
σ
© 2003 Prentice-Hall, Inc.
Chap 8-4
Examples of CI for Proportions
 How many of you are satisfied with the with the
the Streets are cleaned in Phnom Penh?
 10 People
 Number who say Yes = Number who say No =
 Proportion = No/(Total who Answered)
 How confident are you this represents the whole
of the class?
© 2003 Prentice-Hall, Inc.
Chap 8-5
Estimation Process
Mean, µ, is
unknown
Population Random
Sample I am 95%
confident that µ
is between 40 &
60.
Mean
X = 50
Sample
© 2003 Prentice-Hall, Inc.
Chap 8-6
Point Estimates
Estimate Population
Parameters …
with Sample
Statistics
Mean
Proportion
Variance
Difference
µ
p
2
σ
1 2µ µ−
X
SP
2
S
1 2X X−
© 2003 Prentice-Hall, Inc.
Chap 8-7
Interval Estimates
 Provide Range of Values
 Take into consideration variation in sample
statistics from sample to sample
 Based on observation from 1 sample
 Give information about closeness to unknown
population parameters
 Stated in terms of level of confidence

Never 100% sure
© 2003 Prentice-Hall, Inc.
Chap 8-8
Confidence Interval Estimates
Mean
σ Unknown
Confidence
Intervals
Proportion
σ Known
© 2003 Prentice-Hall, Inc.
Chap 8-9
Confidence Interval for
( Known)
 Assumptions
 Population standard deviation is known
 Population is normally distributed
 If population is not normal, use large sample
 Confidence Interval Estimate

 is called the sampling error or
margin of error
µ
σ
/ 2 /2X Z X Z
n n
α α
σ σ
µ− ≤ ≤ +
Standard Error
Critical Value
/ 2e Z
n
α
σ
=
© 2003 Prentice-Hall, Inc.
Chap 8-10
Elements of Confidence Interval
Estimation
 Level of Confidence
 Confidence that the interval will contain the
unknown population parameter
 Precision (Range)
 Closeness to the unknown parameter
 Cost
 Cost required to obtain a sample of size n
© 2003 Prentice-Hall, Inc.
Chap 8-11
Level of Confidence
 Denoted by
 A Relative Frequency Interpretation
 In the long run, of all the confidence
intervals that can be constructed will contain
(bracket) the unknown parameter
 A Specific Interval Will Either Contain or Not
Contain the Parameter
 No probability involved in a specific interval
( )100 1 %α−
( )100 1 %α−
© 2003 Prentice-Hall, Inc.
Chap 8-12
Interval and Level of Confidence
Confidence
Intervals
extend from
to
of intervals
constructed
contain ;
do
not.
_Sampling Distribution of the Mean
X
X Zσ−
X
σ
/ 2α
/ 2α
X
X
µ µ=
1 α−
X
X Zσ+
( )1 100%α−
µ
100 %α
/ 2 X
Zαµ σ+/ 2 X
Zαµ σ−
© 2003 Prentice-Hall, Inc.
Chap 8-13
Step 3 :Z is found by
looking Table Value on Page
811
How to find the Z Value based on
a Confidence Interval (CI)
/ 2α
/ 2α
X
X
µ µ=
1 α−
/ 2 X
Zαµ σ+
/ 2αTable
Value
Table Value = 1- / 2α
/2α
Z /2α
Step 1. Find / 2α
)
100
CI
(−1=α
Step 2. Find Table Value
Step 4 :Find CI
/ 2 / 2X Z X Z
n n
α α
σ σ
µ− ≤ ≤ +
© 2003 Prentice-Hall, Inc.
Chap 8-14
Z Values for Typical Confidence Intervals (CI)
90 1.64
95 1.96
99 2.58
99.9 3.29
Step 3 :Z is found by
looking Table Value on
Page 811
/ 2α
/ 2α
X
<---CI--
/ 2 / 2X Z X Z
n n
α α
σ σ
µ− ≤ ≤ +
/2αConfidence
Interval
© 2003 Prentice-Hall, Inc.
Chap 8-15
Example
A random sample of 10 heights
showed an mean heights of
students in a class was 1.5
meters. It is believed that the
population of Cambodian male
heights is a standard
deviation of 0.1 meters and is
very close to a normal
distribution. Construct a 95%
confidence interval for the
average heights of people in the
class. Interpret your result.
85309 344690µ< <
The 95% CI for the population mean:
Sample mean 1.50
Stand Deviation 0.10
Sample Size (Number of Students) = 15
Confidence Interval 95
Zfrom table P811 1.96
Upper Confidence Interval 1.55
Lower Confidence Interval 1.45
95% Confident Interval that the population
mean is between: -
Microsoft Excel
Worksheet
© 2003 Prentice-Hall, Inc.
Chap 8-16
Example: Interpretation
(continued)
We are 95% confident that the Cambodian male number
population average of height is between 1.55 meters
and 1.45 meters.
If all possible samples of size 15 are taken and the
corresponding 95% confidence intervals are constructed,
95% of the confidence intervals that are constructed will
contain the true unknown population mean.
For this particular confidence interval [1.45 meters , 1.55
meters], the unknown population mean can either be in
the interval or not in the interval. It is, therefore,
incorrect to state that the probability is 95% that the
unknown population mean will be in the interval [1.45
meters , 1.55 meters],
© 2003 Prentice-Hall, Inc.
Chap 8-17
Example: Interpretation
(continued)
Using the confidence interval method on repeated
sampling, the probability that we will have constructed a
confidence interval that will contain the unknown
population mean is 95%.
© 2003 Prentice-Hall, Inc.
Chap 8-18
Factors Affecting Interval Width
(Precision)
 Data Variation
 Measured by
 Sample Size

 Level of Confidence

Intervals Extend from
© 1984-1994 T/Maker Co.
X - Zσ to X + Z σ
xx
σ
X
n
σ
σ =
( )100 1 %α−
© 2003 Prentice-Hall, Inc.
Chap 8-19
 Assumptions
 Population standard deviation is unknown
 Population is normally distributed
 If population is not normal, use large sample
 Use Student’s t Distribution
 Confidence Interval Estimate

Confidence Interval for
( Unknown)
µ
σ
/ 2, 1 /2, 1n n
S S
X t X t
n n
α αµ− −− ≤ ≤ +
Margin of Error
Standard Error
© 2003 Prentice-Hall, Inc.
Chap 8-20
Student’s t Distribution
Z
t
0
t (df = 5)
t (df = 13)
Bell-Shaped
Symmetric
‘Fatter’
Tails
Standard
Normal
© 2003 Prentice-Hall, Inc.
Chap 8-21
Student’s t Table
Upper Tail Area
df .25 .10 .05
1 1.000 3.078 6.314
2 0.817 1.886 2.920
3 0.765 1.638 2.353
t0 2.920
t Values
Let: n = 3
df = n - 1 = 2
α = .10
α/2 =.05
α / 2 = .
05
© 2003 Prentice-Hall, Inc.
Chap 8-22
Step 3 : The Critical Value t is found by looking Table Value
on Page 812 and Page 813
How to find the t Value based on
a Confidence Interval (CI)
/ 2α
/ 2α
X
X
µ µ=
1 α−
/ 2 X
Zαµ σ+
UTA = / 2α
1, −/2 nα
Step 1. Find / 2α
)
100
CI
(−1=α
Step 2. Find Upper Tail Area (UTA)
t 1, −/2 nα
/ 2, 1 / 2, 1n n
S S
X t X t
n n
α αµ− −− ≤ ≤ +Step 4 : Find CI
© 2003 Prentice-Hall, Inc.
Chap 8-23
Example
/2, 1 /2, 1
8 8
50 2.0639 50 2.0639
25 25
46.69 53.30
n n
S S
X t X t
n n
α αµ
µ
µ
− −− ≤ ≤ +
− ≤ ≤ +
≤ ≤
A random sample of 25 has 50 and 8.
Set up a 95% confidence interval estimate for
n X S
µ
= = =
We are 95% confident that the unknown true population
mean is somewhere between 46.69 and 53.30.
.
© 2003 Prentice-Hall, Inc.
Chap 8-24
 PHStat | Confidence Interval | Estimate for the
Mean, Sigma Unknown
 Example in Excel Spreadsheet
Confidence Interval for
( Unknown) in PHStat
µ
σ
Microsoft Excel
Worksheet
Confidence Interval Estimate for the Mean
Data
Sample Standard Deviation 8
Sample Mean 50
Sample Size 25
Confidence Level 95%
Standard Error of the Mean 1.6
Degrees of Freedom 24
t Value 2.063898137
Interval Half Width 3.302237019
Interval Lower Limit 46.70
Interval Upper Limit 53.30
Intermediate Calculations
Confidence Interval
© 2003 Prentice-Hall, Inc.
Chap 8-25
Confidence Interval Estimate
for Proportion
 Assumptions
 Two categorical outcomes
 Population follows binomial distribution
 Normal approximation can be used if
and
 Confidence Interval Estimate

5np ≥ ( )1 5n p− ≥
( ) ( )
/ 2 / 2
1 1S S S S
S S
p p p p
p Z p p Z
n n
α α
− −
− ≤ ≤ +
Margin of Error
Standard Error
© 2003 Prentice-Hall, Inc.
Chap 8-26
Example
A random sample of 400 voters showed that 32
preferred Candidate A. Set up a 95% confidence interval
estimate for p.
( ) ( )
( ) ( )
/ /
1 1
.08 1 .08 .08 1 .08
.08 1.96 .08 1.96
400 400
.053 .107
s s s s
s s
p p p p
p Z p p Z
n n
p
p
α α2 2
− −
− ≤ ≤ +
− −
− ≤ ≤ +
≤ ≤
We are 95% confident that the proportion of voters who
prefer Candidate A is somewhere between 0.053 and
0.107.
© 2003 Prentice-Hall, Inc.
Chap 8-27
Confidence Interval Estimate for
Proportion in PHStat
 PHStat | Confidence Interval | Estimate for the
Proportion …
 Example in Excel Spreadsheet
Microsoft Excel
Worksheet
Confidence Interval Estimate for the Mean
Data
Sample Size 400
Number of Successes 32
Confidence Level 95%
Sample Proportion 0.08
Z Value -1.95996108
Standard Error of the Proportion 0.01356466
Interval Half Width 0.026586206
Interval Lower Limit 0.053413794
Interval Upper Limit 0.106586206
Intermediate Calculations
Confidence Interval
© 2003 Prentice-Hall, Inc.
Chap 8-28
Ethical Issues
 Confidence Interval (Reflects Sampling Error)
Should Always Be Reported Along with the
Point Estimate
 The Level of Confidence Should Always Be
Reported
 The Sample Size Should Be Reported
 An Interpretation of the Confidence Interval
Estimate Should Also Be Provided
© 2003 Prentice-Hall, Inc.
Chap 8-29
Chapter Summary
 Illustrated Estimation Process
 Discussed Point Estimates
 Addressed Interval Estimates
 Discussed Confidence Interval Estimation
for the Mean ( Known)
 Discussed Confidence Interval Estimation
for the Mean ( Unknown)
σ
σ
© 2003 Prentice-Hall, Inc.
Chap 8-30
Chapter Summary
 Discussed Confidence Interval Estimation for
the Proportion
 Addressed Confidence Interval Estimation
and Ethical Issues
(continued)

More Related Content

What's hot

Business Statistics Chapter 3
Business Statistics Chapter 3Business Statistics Chapter 3
Business Statistics Chapter 3
Lux PP
 
LECTURE 1 ONE SAMPLE T TEST.ppt
LECTURE 1 ONE SAMPLE T TEST.pptLECTURE 1 ONE SAMPLE T TEST.ppt
LECTURE 1 ONE SAMPLE T TEST.ppt
KEHKASHANNIZAM
 
Chap06 normal distributions & continous
Chap06 normal distributions & continousChap06 normal distributions & continous
Chap06 normal distributions & continous
Uni Azza Aunillah
 
Basic business statistics 2
Basic business statistics 2Basic business statistics 2
Basic business statistics 2
Anwar Afridi
 
Chapter 10
Chapter 10Chapter 10
Chapter 10
Tuul Tuul
 
Fundamentals of Testing Hypothesis
Fundamentals of Testing HypothesisFundamentals of Testing Hypothesis
Fundamentals of Testing Hypothesis
Yesica Adicondro
 
Chap06 sampling and sampling distributions
Chap06 sampling and sampling distributionsChap06 sampling and sampling distributions
Chap06 sampling and sampling distributions
Judianto Nugroho
 
Chap05 discrete probability distributions
Chap05 discrete probability distributionsChap05 discrete probability distributions
Chap05 discrete probability distributions
Uni Azza Aunillah
 
Chap09 2 sample test
Chap09 2 sample testChap09 2 sample test
Chap09 2 sample test
Uni Azza Aunillah
 
Bbs11 ppt ch08
Bbs11 ppt ch08Bbs11 ppt ch08
Bbs11 ppt ch08
Tuul Tuul
 
Bbs11 ppt ch10
Bbs11 ppt ch10Bbs11 ppt ch10
Bbs11 ppt ch10
Tuul Tuul
 
Chap03 numerical descriptive measures
Chap03 numerical descriptive measuresChap03 numerical descriptive measures
Chap03 numerical descriptive measures
Uni Azza Aunillah
 
Chap04 basic probability
Chap04 basic probabilityChap04 basic probability
Chap04 basic probability
Uni Azza Aunillah
 
Testing Hypothesis
Testing HypothesisTesting Hypothesis
Testing Hypothesis
Azmi Mohd Tamil
 
Simple Linear Regression
Simple Linear RegressionSimple Linear Regression
Simple Linear Regression
Yesica Adicondro
 
Point and Interval Estimation
Point and Interval EstimationPoint and Interval Estimation
Point and Interval Estimation
Shubham Mehta
 
Applied Business Statistics ,ken black , ch 6
Applied Business Statistics ,ken black , ch 6Applied Business Statistics ,ken black , ch 6
Applied Business Statistics ,ken black , ch 6
AbdelmonsifFadl
 
09 ch ken black solution
09 ch ken black solution09 ch ken black solution
09 ch ken black solution
Krunal Shah
 
Chapter 3 260110 044503
Chapter 3 260110 044503Chapter 3 260110 044503
Chapter 3 260110 044503
guest25d353
 
Chap01 intro & data collection
Chap01 intro & data collectionChap01 intro & data collection
Chap01 intro & data collection
Uni Azza Aunillah
 

What's hot (20)

Business Statistics Chapter 3
Business Statistics Chapter 3Business Statistics Chapter 3
Business Statistics Chapter 3
 
LECTURE 1 ONE SAMPLE T TEST.ppt
LECTURE 1 ONE SAMPLE T TEST.pptLECTURE 1 ONE SAMPLE T TEST.ppt
LECTURE 1 ONE SAMPLE T TEST.ppt
 
Chap06 normal distributions & continous
Chap06 normal distributions & continousChap06 normal distributions & continous
Chap06 normal distributions & continous
 
Basic business statistics 2
Basic business statistics 2Basic business statistics 2
Basic business statistics 2
 
Chapter 10
Chapter 10Chapter 10
Chapter 10
 
Fundamentals of Testing Hypothesis
Fundamentals of Testing HypothesisFundamentals of Testing Hypothesis
Fundamentals of Testing Hypothesis
 
Chap06 sampling and sampling distributions
Chap06 sampling and sampling distributionsChap06 sampling and sampling distributions
Chap06 sampling and sampling distributions
 
Chap05 discrete probability distributions
Chap05 discrete probability distributionsChap05 discrete probability distributions
Chap05 discrete probability distributions
 
Chap09 2 sample test
Chap09 2 sample testChap09 2 sample test
Chap09 2 sample test
 
Bbs11 ppt ch08
Bbs11 ppt ch08Bbs11 ppt ch08
Bbs11 ppt ch08
 
Bbs11 ppt ch10
Bbs11 ppt ch10Bbs11 ppt ch10
Bbs11 ppt ch10
 
Chap03 numerical descriptive measures
Chap03 numerical descriptive measuresChap03 numerical descriptive measures
Chap03 numerical descriptive measures
 
Chap04 basic probability
Chap04 basic probabilityChap04 basic probability
Chap04 basic probability
 
Testing Hypothesis
Testing HypothesisTesting Hypothesis
Testing Hypothesis
 
Simple Linear Regression
Simple Linear RegressionSimple Linear Regression
Simple Linear Regression
 
Point and Interval Estimation
Point and Interval EstimationPoint and Interval Estimation
Point and Interval Estimation
 
Applied Business Statistics ,ken black , ch 6
Applied Business Statistics ,ken black , ch 6Applied Business Statistics ,ken black , ch 6
Applied Business Statistics ,ken black , ch 6
 
09 ch ken black solution
09 ch ken black solution09 ch ken black solution
09 ch ken black solution
 
Chapter 3 260110 044503
Chapter 3 260110 044503Chapter 3 260110 044503
Chapter 3 260110 044503
 
Chap01 intro & data collection
Chap01 intro & data collectionChap01 intro & data collection
Chap01 intro & data collection
 

Similar to Business Statistics Chapter 8

Msb12e ppt ch06
Msb12e ppt ch06Msb12e ppt ch06
Msb12e ppt ch06
Subas Nandy
 
Ch08(1)
Ch08(1)Ch08(1)
Ch08(2)
Ch08(2)Ch08(2)
Lesson04_Static11
Lesson04_Static11Lesson04_Static11
Lesson04_Static11
thangv
 
Lesson04_new
Lesson04_newLesson04_new
Lesson04_new
shengvn
 
Estimating population values ppt @ bec doms
Estimating population values ppt @ bec domsEstimating population values ppt @ bec doms
Estimating population values ppt @ bec doms
Babasab Patil
 
Statistik 1 7 estimasi & ci
Statistik 1 7 estimasi & ciStatistik 1 7 estimasi & ci
Statistik 1 7 estimasi & ci
Selvin Hadi
 
Chap008.ppt
Chap008.pptChap008.ppt
Chap008.ppt
najwalyaa
 
Business Analytics _ Confidence Interval
Business Analytics _ Confidence IntervalBusiness Analytics _ Confidence Interval
Business Analytics _ Confidence Interval
Ravindra Nath Shukla
 
Chap08
Chap08Chap08
Chapter on Confidence interval notes.ppt
Chapter on Confidence interval notes.pptChapter on Confidence interval notes.ppt
Chapter on Confidence interval notes.ppt
AbdulMuhith4
 
Stats chapter 10
Stats chapter 10Stats chapter 10
Stats chapter 10
Richard Ferreria
 
BUS173 Lecture 5.pdf
BUS173 Lecture 5.pdfBUS173 Lecture 5.pdf
BUS173 Lecture 5.pdf
SusantoSaha1
 
Lec 5 statistical intervals
Lec 5 statistical intervalsLec 5 statistical intervals
Lec 5 statistical intervals
cairo university
 
Confidence interval & probability statements
Confidence interval & probability statements Confidence interval & probability statements
Confidence interval & probability statements
DrZahid Khan
 
Chapter 7 Section 3.ppt
Chapter 7 Section 3.pptChapter 7 Section 3.ppt
Chapter 7 Section 3.ppt
ManoloTaquire
 
Montgomery
Montgomery Montgomery
Montgomery
bazz8
 
Estimation and confidence interval
Estimation and confidence intervalEstimation and confidence interval
Estimation and confidence interval
Homework Guru
 
Estimating a Population Mean
Estimating a Population Mean  Estimating a Population Mean
Estimating a Population Mean
Long Beach City College
 
Practice Test 3B Solution
Practice Test 3B SolutionPractice Test 3B Solution
Practice Test 3B Solution
Long Beach City College
 

Similar to Business Statistics Chapter 8 (20)

Msb12e ppt ch06
Msb12e ppt ch06Msb12e ppt ch06
Msb12e ppt ch06
 
Ch08(1)
Ch08(1)Ch08(1)
Ch08(1)
 
Ch08(2)
Ch08(2)Ch08(2)
Ch08(2)
 
Lesson04_Static11
Lesson04_Static11Lesson04_Static11
Lesson04_Static11
 
Lesson04_new
Lesson04_newLesson04_new
Lesson04_new
 
Estimating population values ppt @ bec doms
Estimating population values ppt @ bec domsEstimating population values ppt @ bec doms
Estimating population values ppt @ bec doms
 
Statistik 1 7 estimasi & ci
Statistik 1 7 estimasi & ciStatistik 1 7 estimasi & ci
Statistik 1 7 estimasi & ci
 
Chap008.ppt
Chap008.pptChap008.ppt
Chap008.ppt
 
Business Analytics _ Confidence Interval
Business Analytics _ Confidence IntervalBusiness Analytics _ Confidence Interval
Business Analytics _ Confidence Interval
 
Chap08
Chap08Chap08
Chap08
 
Chapter on Confidence interval notes.ppt
Chapter on Confidence interval notes.pptChapter on Confidence interval notes.ppt
Chapter on Confidence interval notes.ppt
 
Stats chapter 10
Stats chapter 10Stats chapter 10
Stats chapter 10
 
BUS173 Lecture 5.pdf
BUS173 Lecture 5.pdfBUS173 Lecture 5.pdf
BUS173 Lecture 5.pdf
 
Lec 5 statistical intervals
Lec 5 statistical intervalsLec 5 statistical intervals
Lec 5 statistical intervals
 
Confidence interval & probability statements
Confidence interval & probability statements Confidence interval & probability statements
Confidence interval & probability statements
 
Chapter 7 Section 3.ppt
Chapter 7 Section 3.pptChapter 7 Section 3.ppt
Chapter 7 Section 3.ppt
 
Montgomery
Montgomery Montgomery
Montgomery
 
Estimation and confidence interval
Estimation and confidence intervalEstimation and confidence interval
Estimation and confidence interval
 
Estimating a Population Mean
Estimating a Population Mean  Estimating a Population Mean
Estimating a Population Mean
 
Practice Test 3B Solution
Practice Test 3B SolutionPractice Test 3B Solution
Practice Test 3B Solution
 

More from Lux PP

International Business Chapter 16
International Business Chapter 16International Business Chapter 16
International Business Chapter 16
Lux PP
 
International Business Chapter 13
International Business Chapter 13International Business Chapter 13
International Business Chapter 13
Lux PP
 
International Business Chapter 12
International Business Chapter 12International Business Chapter 12
International Business Chapter 12
Lux PP
 
International Business Chapter 11
International Business Chapter 11International Business Chapter 11
International Business Chapter 11
Lux PP
 
International Business Chapter 10
International Business Chapter 10International Business Chapter 10
International Business Chapter 10
Lux PP
 
International Business Chapter 9
International Business Chapter 9International Business Chapter 9
International Business Chapter 9
Lux PP
 
International Business Chapter 08
International Business Chapter 08International Business Chapter 08
International Business Chapter 08
Lux PP
 
International Business Chapter 07
International Business Chapter 07International Business Chapter 07
International Business Chapter 07
Lux PP
 
International Business Chapter 06
International Business Chapter 06International Business Chapter 06
International Business Chapter 06
Lux PP
 
International Business Chapter 11
International Business Chapter 11International Business Chapter 11
International Business Chapter 11
Lux PP
 
Business Statistics Chapter 1
Business Statistics Chapter 1Business Statistics Chapter 1
Business Statistics Chapter 1
Lux PP
 

More from Lux PP (11)

International Business Chapter 16
International Business Chapter 16International Business Chapter 16
International Business Chapter 16
 
International Business Chapter 13
International Business Chapter 13International Business Chapter 13
International Business Chapter 13
 
International Business Chapter 12
International Business Chapter 12International Business Chapter 12
International Business Chapter 12
 
International Business Chapter 11
International Business Chapter 11International Business Chapter 11
International Business Chapter 11
 
International Business Chapter 10
International Business Chapter 10International Business Chapter 10
International Business Chapter 10
 
International Business Chapter 9
International Business Chapter 9International Business Chapter 9
International Business Chapter 9
 
International Business Chapter 08
International Business Chapter 08International Business Chapter 08
International Business Chapter 08
 
International Business Chapter 07
International Business Chapter 07International Business Chapter 07
International Business Chapter 07
 
International Business Chapter 06
International Business Chapter 06International Business Chapter 06
International Business Chapter 06
 
International Business Chapter 11
International Business Chapter 11International Business Chapter 11
International Business Chapter 11
 
Business Statistics Chapter 1
Business Statistics Chapter 1Business Statistics Chapter 1
Business Statistics Chapter 1
 

Recently uploaded

TriStar Gold Corporate Presentation - June 2024
TriStar Gold Corporate Presentation - June 2024TriStar Gold Corporate Presentation - June 2024
TriStar Gold Corporate Presentation - June 2024
Adnet Communications
 
➒➌➎➏➑➐➋➑➐➐ Satta Matka Dpboss Matka Guessing Indian Matka
➒➌➎➏➑➐➋➑➐➐ Satta Matka Dpboss Matka Guessing Indian Matka➒➌➎➏➑➐➋➑➐➐ Satta Matka Dpboss Matka Guessing Indian Matka
➒➌➎➏➑➐➋➑➐➐ Satta Matka Dpboss Matka Guessing Indian Matka
➒➌➎➏➑➐➋➑➐➐Dpboss Matka Guessing Satta Matka Kalyan Chart Indian Matka
 
Truck Loading Conveyor Manufacturers Chennai
Truck Loading Conveyor Manufacturers ChennaiTruck Loading Conveyor Manufacturers Chennai
Truck Loading Conveyor Manufacturers Chennai
ConveyorSystem
 
Satta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results Kalyan ChartSatta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results
 
一比一原版(UCSC毕业证)加州大学圣克鲁兹分校毕业证如何办理
一比一原版(UCSC毕业证)加州大学圣克鲁兹分校毕业证如何办理一比一原版(UCSC毕业证)加州大学圣克鲁兹分校毕业证如何办理
一比一原版(UCSC毕业证)加州大学圣克鲁兹分校毕业证如何办理
taqyea
 
DPboss Indian Satta Matta Matka Result Fix Matka Number
DPboss Indian Satta Matta Matka Result Fix Matka NumberDPboss Indian Satta Matta Matka Result Fix Matka Number
DPboss Indian Satta Matta Matka Result Fix Matka Number
Satta Matka
 
Leading the Development of Profitable and Sustainable Products
Leading the Development of Profitable and Sustainable ProductsLeading the Development of Profitable and Sustainable Products
Leading the Development of Profitable and Sustainable Products
Aggregage
 
Satta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results Kalyan ChartSatta Matka Dpboss Kalyan Matka Results Kalyan Chart
Kanban Coaching Exchange with Dave White - Sample SDR Report
Kanban Coaching Exchange with Dave White - Sample SDR ReportKanban Coaching Exchange with Dave White - Sample SDR Report
Kanban Coaching Exchange with Dave White - Sample SDR Report
Helen Meek
 
DP boss matka results IndiaMART Kalyan guessing
DP boss matka results IndiaMART Kalyan guessingDP boss matka results IndiaMART Kalyan guessing
DP boss matka results IndiaMART Kalyan guessing
➑➌➋➑➒➎➑➑➊➍
 
一比一原版(Lehigh毕业证)利哈伊大学毕业证如何办理
一比一原版(Lehigh毕业证)利哈伊大学毕业证如何办理一比一原版(Lehigh毕业证)利哈伊大学毕业证如何办理
一比一原版(Lehigh毕业证)利哈伊大学毕业证如何办理
taqyea
 
It takes all kinds of AI and Humans to make Good Business Decision
It takes all kinds of AI and Humans to make Good Business DecisionIt takes all kinds of AI and Humans to make Good Business Decision
It takes all kinds of AI and Humans to make Good Business Decision
Denis Gagné
 
Satta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results Kalyan ChartSatta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results
 
RFHIC, IMS 2024, Washington D.C., tradeshow
RFHIC, IMS 2024, Washington D.C., tradeshowRFHIC, IMS 2024, Washington D.C., tradeshow
RFHIC, IMS 2024, Washington D.C., tradeshow
SeungyeonRyu2
 
Kanban Coaching Exchange with Dave White - Example SDR Report
Kanban Coaching Exchange with Dave White - Example SDR ReportKanban Coaching Exchange with Dave White - Example SDR Report
Kanban Coaching Exchange with Dave White - Example SDR Report
Helen Meek
 
Progress Report - Qualcomm AI Workshop - AI available - everywhereAI summit 1...
Progress Report - Qualcomm AI Workshop - AI available - everywhereAI summit 1...Progress Report - Qualcomm AI Workshop - AI available - everywhereAI summit 1...
Progress Report - Qualcomm AI Workshop - AI available - everywhereAI summit 1...
Holger Mueller
 
Askxx.com Complete Pitch Deck Course Online
Askxx.com Complete Pitch Deck Course OnlineAskxx.com Complete Pitch Deck Course Online
Askxx.com Complete Pitch Deck Course Online
AskXX.com
 
Stainless Steel Conveyor Manufacturers Chennai
Stainless Steel Conveyor Manufacturers ChennaiStainless Steel Conveyor Manufacturers Chennai
Stainless Steel Conveyor Manufacturers Chennai
ConveyorSystem
 
Satta matka guessing Kalyan fxxjodi panna
Satta matka guessing Kalyan fxxjodi pannaSatta matka guessing Kalyan fxxjodi panna
Satta matka guessing Kalyan fxxjodi panna
➑➌➋➑➒➎➑➑➊➍
 
The Key Summaries of Forum Gas 2024.pptx
The Key Summaries of Forum Gas 2024.pptxThe Key Summaries of Forum Gas 2024.pptx
The Key Summaries of Forum Gas 2024.pptx
Sampe Purba
 

Recently uploaded (20)

TriStar Gold Corporate Presentation - June 2024
TriStar Gold Corporate Presentation - June 2024TriStar Gold Corporate Presentation - June 2024
TriStar Gold Corporate Presentation - June 2024
 
➒➌➎➏➑➐➋➑➐➐ Satta Matka Dpboss Matka Guessing Indian Matka
➒➌➎➏➑➐➋➑➐➐ Satta Matka Dpboss Matka Guessing Indian Matka➒➌➎➏➑➐➋➑➐➐ Satta Matka Dpboss Matka Guessing Indian Matka
➒➌➎➏➑➐➋➑➐➐ Satta Matka Dpboss Matka Guessing Indian Matka
 
Truck Loading Conveyor Manufacturers Chennai
Truck Loading Conveyor Manufacturers ChennaiTruck Loading Conveyor Manufacturers Chennai
Truck Loading Conveyor Manufacturers Chennai
 
Satta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results Kalyan ChartSatta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results Kalyan Chart
 
一比一原版(UCSC毕业证)加州大学圣克鲁兹分校毕业证如何办理
一比一原版(UCSC毕业证)加州大学圣克鲁兹分校毕业证如何办理一比一原版(UCSC毕业证)加州大学圣克鲁兹分校毕业证如何办理
一比一原版(UCSC毕业证)加州大学圣克鲁兹分校毕业证如何办理
 
DPboss Indian Satta Matta Matka Result Fix Matka Number
DPboss Indian Satta Matta Matka Result Fix Matka NumberDPboss Indian Satta Matta Matka Result Fix Matka Number
DPboss Indian Satta Matta Matka Result Fix Matka Number
 
Leading the Development of Profitable and Sustainable Products
Leading the Development of Profitable and Sustainable ProductsLeading the Development of Profitable and Sustainable Products
Leading the Development of Profitable and Sustainable Products
 
Satta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results Kalyan ChartSatta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results Kalyan Chart
 
Kanban Coaching Exchange with Dave White - Sample SDR Report
Kanban Coaching Exchange with Dave White - Sample SDR ReportKanban Coaching Exchange with Dave White - Sample SDR Report
Kanban Coaching Exchange with Dave White - Sample SDR Report
 
DP boss matka results IndiaMART Kalyan guessing
DP boss matka results IndiaMART Kalyan guessingDP boss matka results IndiaMART Kalyan guessing
DP boss matka results IndiaMART Kalyan guessing
 
一比一原版(Lehigh毕业证)利哈伊大学毕业证如何办理
一比一原版(Lehigh毕业证)利哈伊大学毕业证如何办理一比一原版(Lehigh毕业证)利哈伊大学毕业证如何办理
一比一原版(Lehigh毕业证)利哈伊大学毕业证如何办理
 
It takes all kinds of AI and Humans to make Good Business Decision
It takes all kinds of AI and Humans to make Good Business DecisionIt takes all kinds of AI and Humans to make Good Business Decision
It takes all kinds of AI and Humans to make Good Business Decision
 
Satta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results Kalyan ChartSatta Matka Dpboss Kalyan Matka Results Kalyan Chart
Satta Matka Dpboss Kalyan Matka Results Kalyan Chart
 
RFHIC, IMS 2024, Washington D.C., tradeshow
RFHIC, IMS 2024, Washington D.C., tradeshowRFHIC, IMS 2024, Washington D.C., tradeshow
RFHIC, IMS 2024, Washington D.C., tradeshow
 
Kanban Coaching Exchange with Dave White - Example SDR Report
Kanban Coaching Exchange with Dave White - Example SDR ReportKanban Coaching Exchange with Dave White - Example SDR Report
Kanban Coaching Exchange with Dave White - Example SDR Report
 
Progress Report - Qualcomm AI Workshop - AI available - everywhereAI summit 1...
Progress Report - Qualcomm AI Workshop - AI available - everywhereAI summit 1...Progress Report - Qualcomm AI Workshop - AI available - everywhereAI summit 1...
Progress Report - Qualcomm AI Workshop - AI available - everywhereAI summit 1...
 
Askxx.com Complete Pitch Deck Course Online
Askxx.com Complete Pitch Deck Course OnlineAskxx.com Complete Pitch Deck Course Online
Askxx.com Complete Pitch Deck Course Online
 
Stainless Steel Conveyor Manufacturers Chennai
Stainless Steel Conveyor Manufacturers ChennaiStainless Steel Conveyor Manufacturers Chennai
Stainless Steel Conveyor Manufacturers Chennai
 
Satta matka guessing Kalyan fxxjodi panna
Satta matka guessing Kalyan fxxjodi pannaSatta matka guessing Kalyan fxxjodi panna
Satta matka guessing Kalyan fxxjodi panna
 
The Key Summaries of Forum Gas 2024.pptx
The Key Summaries of Forum Gas 2024.pptxThe Key Summaries of Forum Gas 2024.pptx
The Key Summaries of Forum Gas 2024.pptx
 

Business Statistics Chapter 8

  • 1. © 2003 Prentice-Hall, Inc. Chap 8-1 Basic Business Statistics (9th Edition) Chapter 8 Confidence Interval Estimation
  • 2. © 2003 Prentice-Hall, Inc. Chap 8-2 Chapter Topics  Estimation Process  Point Estimates  Interval Estimates  Confidence Interval Estimation for the Mean ( Known )  Confidence Interval Estimation for the Mean ( Unknown )  Confidence Interval Estimation for the Proportion σ σ
  • 3. © 2003 Prentice-Hall, Inc. Chap 8-3 Examples of where CI are is used (continued) CI of Means 1000 Salaries of people in Phnom Penh: Sample Mean = How confident are you this is the same as the Population Mean Salary of the Phnom Pehn? (The average if you had all the data for every one in Phnom Phen) Two Methods to work this out: - 1. Confidence Interval Estimation for the Mean ( Known ) You could use the Standard Deviation of men in Cambodia 2. Confidence Interval Estimation for the Mean ( Unknown ) σ σ
  • 4. © 2003 Prentice-Hall, Inc. Chap 8-4 Examples of CI for Proportions  How many of you are satisfied with the with the the Streets are cleaned in Phnom Penh?  10 People  Number who say Yes = Number who say No =  Proportion = No/(Total who Answered)  How confident are you this represents the whole of the class?
  • 5. © 2003 Prentice-Hall, Inc. Chap 8-5 Estimation Process Mean, µ, is unknown Population Random Sample I am 95% confident that µ is between 40 & 60. Mean X = 50 Sample
  • 6. © 2003 Prentice-Hall, Inc. Chap 8-6 Point Estimates Estimate Population Parameters … with Sample Statistics Mean Proportion Variance Difference µ p 2 σ 1 2µ µ− X SP 2 S 1 2X X−
  • 7. © 2003 Prentice-Hall, Inc. Chap 8-7 Interval Estimates  Provide Range of Values  Take into consideration variation in sample statistics from sample to sample  Based on observation from 1 sample  Give information about closeness to unknown population parameters  Stated in terms of level of confidence  Never 100% sure
  • 8. © 2003 Prentice-Hall, Inc. Chap 8-8 Confidence Interval Estimates Mean σ Unknown Confidence Intervals Proportion σ Known
  • 9. © 2003 Prentice-Hall, Inc. Chap 8-9 Confidence Interval for ( Known)  Assumptions  Population standard deviation is known  Population is normally distributed  If population is not normal, use large sample  Confidence Interval Estimate   is called the sampling error or margin of error µ σ / 2 /2X Z X Z n n α α σ σ µ− ≤ ≤ + Standard Error Critical Value / 2e Z n α σ =
  • 10. © 2003 Prentice-Hall, Inc. Chap 8-10 Elements of Confidence Interval Estimation  Level of Confidence  Confidence that the interval will contain the unknown population parameter  Precision (Range)  Closeness to the unknown parameter  Cost  Cost required to obtain a sample of size n
  • 11. © 2003 Prentice-Hall, Inc. Chap 8-11 Level of Confidence  Denoted by  A Relative Frequency Interpretation  In the long run, of all the confidence intervals that can be constructed will contain (bracket) the unknown parameter  A Specific Interval Will Either Contain or Not Contain the Parameter  No probability involved in a specific interval ( )100 1 %α− ( )100 1 %α−
  • 12. © 2003 Prentice-Hall, Inc. Chap 8-12 Interval and Level of Confidence Confidence Intervals extend from to of intervals constructed contain ; do not. _Sampling Distribution of the Mean X X Zσ− X σ / 2α / 2α X X µ µ= 1 α− X X Zσ+ ( )1 100%α− µ 100 %α / 2 X Zαµ σ+/ 2 X Zαµ σ−
  • 13. © 2003 Prentice-Hall, Inc. Chap 8-13 Step 3 :Z is found by looking Table Value on Page 811 How to find the Z Value based on a Confidence Interval (CI) / 2α / 2α X X µ µ= 1 α− / 2 X Zαµ σ+ / 2αTable Value Table Value = 1- / 2α /2α Z /2α Step 1. Find / 2α ) 100 CI (−1=α Step 2. Find Table Value Step 4 :Find CI / 2 / 2X Z X Z n n α α σ σ µ− ≤ ≤ +
  • 14. © 2003 Prentice-Hall, Inc. Chap 8-14 Z Values for Typical Confidence Intervals (CI) 90 1.64 95 1.96 99 2.58 99.9 3.29 Step 3 :Z is found by looking Table Value on Page 811 / 2α / 2α X <---CI-- / 2 / 2X Z X Z n n α α σ σ µ− ≤ ≤ + /2αConfidence Interval
  • 15. © 2003 Prentice-Hall, Inc. Chap 8-15 Example A random sample of 10 heights showed an mean heights of students in a class was 1.5 meters. It is believed that the population of Cambodian male heights is a standard deviation of 0.1 meters and is very close to a normal distribution. Construct a 95% confidence interval for the average heights of people in the class. Interpret your result. 85309 344690µ< < The 95% CI for the population mean: Sample mean 1.50 Stand Deviation 0.10 Sample Size (Number of Students) = 15 Confidence Interval 95 Zfrom table P811 1.96 Upper Confidence Interval 1.55 Lower Confidence Interval 1.45 95% Confident Interval that the population mean is between: - Microsoft Excel Worksheet
  • 16. © 2003 Prentice-Hall, Inc. Chap 8-16 Example: Interpretation (continued) We are 95% confident that the Cambodian male number population average of height is between 1.55 meters and 1.45 meters. If all possible samples of size 15 are taken and the corresponding 95% confidence intervals are constructed, 95% of the confidence intervals that are constructed will contain the true unknown population mean. For this particular confidence interval [1.45 meters , 1.55 meters], the unknown population mean can either be in the interval or not in the interval. It is, therefore, incorrect to state that the probability is 95% that the unknown population mean will be in the interval [1.45 meters , 1.55 meters],
  • 17. © 2003 Prentice-Hall, Inc. Chap 8-17 Example: Interpretation (continued) Using the confidence interval method on repeated sampling, the probability that we will have constructed a confidence interval that will contain the unknown population mean is 95%.
  • 18. © 2003 Prentice-Hall, Inc. Chap 8-18 Factors Affecting Interval Width (Precision)  Data Variation  Measured by  Sample Size   Level of Confidence  Intervals Extend from © 1984-1994 T/Maker Co. X - Zσ to X + Z σ xx σ X n σ σ = ( )100 1 %α−
  • 19. © 2003 Prentice-Hall, Inc. Chap 8-19  Assumptions  Population standard deviation is unknown  Population is normally distributed  If population is not normal, use large sample  Use Student’s t Distribution  Confidence Interval Estimate  Confidence Interval for ( Unknown) µ σ / 2, 1 /2, 1n n S S X t X t n n α αµ− −− ≤ ≤ + Margin of Error Standard Error
  • 20. © 2003 Prentice-Hall, Inc. Chap 8-20 Student’s t Distribution Z t 0 t (df = 5) t (df = 13) Bell-Shaped Symmetric ‘Fatter’ Tails Standard Normal
  • 21. © 2003 Prentice-Hall, Inc. Chap 8-21 Student’s t Table Upper Tail Area df .25 .10 .05 1 1.000 3.078 6.314 2 0.817 1.886 2.920 3 0.765 1.638 2.353 t0 2.920 t Values Let: n = 3 df = n - 1 = 2 α = .10 α/2 =.05 α / 2 = . 05
  • 22. © 2003 Prentice-Hall, Inc. Chap 8-22 Step 3 : The Critical Value t is found by looking Table Value on Page 812 and Page 813 How to find the t Value based on a Confidence Interval (CI) / 2α / 2α X X µ µ= 1 α− / 2 X Zαµ σ+ UTA = / 2α 1, −/2 nα Step 1. Find / 2α ) 100 CI (−1=α Step 2. Find Upper Tail Area (UTA) t 1, −/2 nα / 2, 1 / 2, 1n n S S X t X t n n α αµ− −− ≤ ≤ +Step 4 : Find CI
  • 23. © 2003 Prentice-Hall, Inc. Chap 8-23 Example /2, 1 /2, 1 8 8 50 2.0639 50 2.0639 25 25 46.69 53.30 n n S S X t X t n n α αµ µ µ − −− ≤ ≤ + − ≤ ≤ + ≤ ≤ A random sample of 25 has 50 and 8. Set up a 95% confidence interval estimate for n X S µ = = = We are 95% confident that the unknown true population mean is somewhere between 46.69 and 53.30. .
  • 24. © 2003 Prentice-Hall, Inc. Chap 8-24  PHStat | Confidence Interval | Estimate for the Mean, Sigma Unknown  Example in Excel Spreadsheet Confidence Interval for ( Unknown) in PHStat µ σ Microsoft Excel Worksheet Confidence Interval Estimate for the Mean Data Sample Standard Deviation 8 Sample Mean 50 Sample Size 25 Confidence Level 95% Standard Error of the Mean 1.6 Degrees of Freedom 24 t Value 2.063898137 Interval Half Width 3.302237019 Interval Lower Limit 46.70 Interval Upper Limit 53.30 Intermediate Calculations Confidence Interval
  • 25. © 2003 Prentice-Hall, Inc. Chap 8-25 Confidence Interval Estimate for Proportion  Assumptions  Two categorical outcomes  Population follows binomial distribution  Normal approximation can be used if and  Confidence Interval Estimate  5np ≥ ( )1 5n p− ≥ ( ) ( ) / 2 / 2 1 1S S S S S S p p p p p Z p p Z n n α α − − − ≤ ≤ + Margin of Error Standard Error
  • 26. © 2003 Prentice-Hall, Inc. Chap 8-26 Example A random sample of 400 voters showed that 32 preferred Candidate A. Set up a 95% confidence interval estimate for p. ( ) ( ) ( ) ( ) / / 1 1 .08 1 .08 .08 1 .08 .08 1.96 .08 1.96 400 400 .053 .107 s s s s s s p p p p p Z p p Z n n p p α α2 2 − − − ≤ ≤ + − − − ≤ ≤ + ≤ ≤ We are 95% confident that the proportion of voters who prefer Candidate A is somewhere between 0.053 and 0.107.
  • 27. © 2003 Prentice-Hall, Inc. Chap 8-27 Confidence Interval Estimate for Proportion in PHStat  PHStat | Confidence Interval | Estimate for the Proportion …  Example in Excel Spreadsheet Microsoft Excel Worksheet Confidence Interval Estimate for the Mean Data Sample Size 400 Number of Successes 32 Confidence Level 95% Sample Proportion 0.08 Z Value -1.95996108 Standard Error of the Proportion 0.01356466 Interval Half Width 0.026586206 Interval Lower Limit 0.053413794 Interval Upper Limit 0.106586206 Intermediate Calculations Confidence Interval
  • 28. © 2003 Prentice-Hall, Inc. Chap 8-28 Ethical Issues  Confidence Interval (Reflects Sampling Error) Should Always Be Reported Along with the Point Estimate  The Level of Confidence Should Always Be Reported  The Sample Size Should Be Reported  An Interpretation of the Confidence Interval Estimate Should Also Be Provided
  • 29. © 2003 Prentice-Hall, Inc. Chap 8-29 Chapter Summary  Illustrated Estimation Process  Discussed Point Estimates  Addressed Interval Estimates  Discussed Confidence Interval Estimation for the Mean ( Known)  Discussed Confidence Interval Estimation for the Mean ( Unknown) σ σ
  • 30. © 2003 Prentice-Hall, Inc. Chap 8-30 Chapter Summary  Discussed Confidence Interval Estimation for the Proportion  Addressed Confidence Interval Estimation and Ethical Issues (continued)
  翻译: