Ken and His Twin Sister Katy Both Took the Same

Multiple Choice

Ken and his twin sister Katy both took the same psychology test but in different classes.On his psychology test,Ken had a score of 110 in a class with a mean of 100 and a standard deviation of 10,while his twin sister Katy had a score of 118 in a class having a mean of 100 and a standard deviation of 18.Which statement is TRUE?

A) Ken's z­score is higher than Katy's.
B) Katy's z­score is higher than Ken's.
C) Both of their z-scores are the same.
D) A z-score cannot be calculated from the information given.