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A set of test scores is normally distributed with a mean of 160 and a standard deviation of 12. Lori received a score of 172. What was her percentile score?

A68%

B84%

C93%

D95%

IDK how to do this!!??! Please explain :)

Verified Answer :

MissPhiladelphia

Since 68% of the distribution is within one standard deviation of the mean, this means that 68/2 = 34% of the distribution lies above the mean and is less than one standard deviation away from the mean. 

 The mean is the halfway point of any normal distribution, so 50% of the distribution lies below the mean. 

 So 50+34 = 84%  distribution lies below the score of 172 because 172 is the point that is above the mean and it is one standard deviation away from the mean of 160.

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