1) The document discusses the normal distribution and its applications in statistical inference. It is the most important probability distribution used to model many continuous variables in biomedical fields. 2) The normal distribution is characterized by its mean and standard deviation. It is perfectly symmetrical and bell-shaped. Properties of the normal curve include that about 68%, 95%, and 99.7% of the data lies within 1, 2, and 3 standard deviations of the mean, respectively. 3) The standard normal distribution is used to convert raw scores to z-scores in order to compare variables measured on different scales. Z-scores indicate how many standard deviations a score is above or below the mean and can be used to determine probabilities, percentiles