STOR 155 Lecture Notes - Lecture 16: Standard Score, Standard Deviation
8 Apr 2015
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Document Summary
Stor 155: introduction to statistics lecture 16: standard normal (3/5/15) Transforming normal x values to z scores: tells you how extreme / unusual / exceptional , allows you to compare distributions, formula, z = (x x) / x, probabilities will be the same as non-standardized, normal distribution. Excel formula: =norm. s. dist (z score, 0 or 1, 0 = height of density function, 1 = area to the left of the cutoff value, =norm. inv (probability) Example problem 1: distribution 1, x = height in inches for males, normal distribution, parameters. = 3: distribution 2, x = height in inches for females, normal distribution, parameters. = 2: an individual male is 76 inches tall. What is his z score: z = (76 70) / 3 = +2 s. d. units, what percent of the population is he taller than, =norm. s. dist (2, 1, = 0. 97725, an individual female is 68 inches tall.
