Z-Scores and the Empirical Rule Flashcards

Vocabulary flashcards covering z-scores, the Empirical Rule, and standard deviation intervals for normal distributions.

Z-score

A value that represents how many standard deviations a given data value falls from the mean of a data set.

Empirical Rule

A rule describing approximately what percentage of data falls within a certain number of standard deviations of the mean in a normally distributed data set.

Empirical Rule ($68\%$ Interval)

The principle that approximately $68\%$ of the data in an approximately normal distribution will have z-scores between $-1$ and $1$.

Empirical Rule ($95\%$ Interval)

The principle that approximately $95\%$ of the data in an approximately normal distribution will have z-scores between $-2$ and $2$.

Empirical Rule ($99.7\%$ Interval)

The principle that all, or almost all, ($99.7\%$) of the data in an approximately normal distribution will have z-scores between $-3$ and $3$.

Normality Assessment using Z-scores

The process of testing a data set to see if it is normally or approximately normally distributed by checking if its z-score distribution matches the Empirical Rule.