SOLUTION: Who did better? Amy,who got an 82 on a test with a mean of 60 and a standard deviation of 15 or Billy, who got a 78 on a test with a mean of 60 and a standard deviation of

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Question 985282: Who did better?
Amy,who got an 82 on a test with a mean of 60 and a standard deviation of 15
or
Billy, who got a 78 on a test with a mean of 60 and a standard deviation of 9?
Answer by reviewermath(1029) About Me  (Show Source):
You can put this solution on YOUR website!
Who did better?
Amy,who got an 82 on a test with a mean of 60 and a standard deviation of 15
or
Billy, who got a 78 on a test with a mean of 60 and a standard deviation of 9?
Solution:
z-score for Amy:
%2882-60%29%2F15 = 1.467
z-score for Billy
%2878-60%29%2F9 = 2
Billy did better because his score is 2 standard deviations above the mean score on his class while Amy's score is only 1.467 standard deviations above the mean score on her class.