The number of hours per day a college student spends on homework has a mean of 6 hours and a standard deviation of 1.25 hours. Yesterday she spent 3 hours on homework. How many standard deviations from the mean is that? Round your answer to two decimal places.
A) 1.20 standard deviations below the mean
B) 1.20 standard deviations above the mean
C) 2.40 standard deviations below the mean
D) 2.40 standard deviations above the mean

Question

Quizplus · Accepted Answer

To find how many standard deviations from the mean the student's homework time is, subtract the mean from the student's time and divide by the standard deviation: (3 - 6) / 1.25 = -2.40. This means the student's time is 2.40 standard deviations below the mean.

The Number of Hours Per Day a College Student Spends