Question

the scores on a standardized test are normally distributed with a mean of 85 and standard deviation of 10. what test score is 0.9 standard deviations below the mean?

Explanation:

Step1: Determine the deviation value

The standard - deviation is 10 and we want 0.9 standard - deviations. So the deviation value is $0.9\times10$.
$0.9\times10 = 9$

Step2: Calculate the test score

The score is below the mean. So we subtract the deviation value from the mean. The mean is 85.
$85−9=76$

Answer:

76