What is a z-score? (Normal Distribution)

z-scores are helpful because they allow us to make inferences about any normal distribution by converting points or values of interest to a value, z, in the standard normal distribution (mean is zero and standard deviation is one).

We can use a z-table to look up z-scores and determine the percent of the distribution above or below the z-score and then relate it back to the distribution we start with.

Also, z-scores are a measure of how many standard distributions a number is away from the mean.

Images used in this video were created using GeoGebra.

0:00 The value of z-scores
0:47 Area under distribution example
2:39 Standard deviation measurement example
3:35 Summary of two topics in video

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