Question

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54. jessica is working two jobs and struggles to find time to study, averaging only 3 hours per week. what percent of students are at least as extreme as jessica, in both directions? (round z score to two decimal places.)

Answer 1

Given:
μ = 9.9 hours, population mean
σ = 4.54 hours, population standard deviation

For the random variable x = 3 hours, the z-score is
z = (3 - 9.92)/4.54 = -1.5242

From standard tables, obtain
P(x ≤ 3) = 0.064 = 6.4%


Answer: 6.4% on both tails of the normal distribution