## The Basic Practice of Statistics 7th Edition

We can use the standardized normal distribution to calculate a standardized score (z-score) that allows us to compare values from two different normal distributions. The z-score is calculated as $z = (x-µ) \div σ$ x is an observation, µ is the mean of the distribution, σ is the standard deviation of the distribution z-score for Idonna = $(670-514) \div 118 = 1.32$ z-score for Jonathan = $(26-20.9) \div 5.3 = .96$