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?

Solution:
z-score for Amy:
{{{(82-60)/15}}} = 1.467
z-score for Billy
{{{(78-60)/9}}} = 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.