Answer:
Hank had a z-score of -1.375.
Jane had a z-score of -2.39.
Jane had the better year relative to their peers, due to her lower z-score.
Explanation:
Z-score:
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
Hank:
ERA of 3.36. For the males, the mean ERA was 4.449 and the standard deviation was 0.792. This means that we have to find Z when
. So



Hank had a z-score of -1.375.
Jane
ERA of 3.49. For the females, the mean ERA was 5.091 and the standard deviation was 0.669. This means that we have to find Z when
. So



Jane had a z-score of -2.39.
Which player had the better year relative to their peers, Hank or Jane
Low ERA is good, high is bad. This means that whoever had the lower z-score had the better year, and in this case, it's Jane