Curves and Distributions

Important information from sections 6.1 and 6.2

Emprical Rule Graph

Empirical Rule:

For a distribution that is symmetrical and bell shaped (in particular, for a normal distribution):

1. Approximately 68% of the data values will lie within 1 standard deviation on each side of the mean

2. Approximately 95% of the data values will lie within 2 standard deviations on each side of the mean

3. Approximately 99.7% (or almost all) of the data values will lie within 3 standard deviations on each side of the mean

Z Score

Section 6.2

Section 6.2

The z value or z score (also known as standard score) gives the number of standard deviations between the original measurement x and the mean u of the x distribution