The Mean Length of Time, Per Week, That Students at a Certain

Multiple Choice

The mean length of time, per week, that students at a certain school spend on their homework is 24.3 hours, with a standard deviation of 1.4 hours. Assuming the distribution of study times is Normal, what percent of students spend more than 25.238 hours per week on homework? Use the fact that the middle 50% of the data falls within 0.67 standard deviations from the mean.

A) 16.5%
B) 5%
C) 12.5%
D) 25%