Find the number of standard deviations from the mean. Round your answer to two decimal places.
-The test scores on the Chapter 10 mathematics test have a mean of 52 and a standard deviation of 10. Andrea scored 86 on the test. How many standard deviations from the mean is that?
A) 3.40 standard deviations below the mean
B) 3.40 standard deviations above the mean
C) 0.49 standard deviations above the mean
D) 0.49 standard deviations below the mean

Question

Quizplus · Accepted Answer

To find the number of standard deviations from the mean, we use the formula:
z = (x - μ) / σ
where z is the number of standard deviations from the mean, x is the score, μ is the mean, and σ is the standard deviation.

Plugging in the values we get:
z = (86 - 52) / 10
z = 3.4

Since Andrea's score is above the mean, the answer is 3.4 standard deviations above the mean, which is choice B.

Find the Number of Standard Deviations from the Mean