Question

5. Determine the null and alternative hypotheses for the following scenario.
a) At Northwest Mississippi Community College, syllabi for online classes state that students should expect
to spend 10 hours per week doing coursework for each three-credit-hour class. The director of eLearning
for the community college is concerned that students are being required to spend more than 10 hours per
week doing work for each three-credit course.

b) After learning that Peter Colat of Switzerland could hold his breath for 19 minutes and 21 seconds under
water, a group of students decided to conduct their science fair project around the amount of time an
average adult can hold his or her breath. Part of the group found research to suggest that adults can hold
their breath for 30.0 seconds when submerged in lukewarm water.

c) Madison, an ambulance driver in a small town, believes that on a typical 24 shift, she receive fewer than
5 emergency call on average. To test this belief, she records the number of calls she receives each shift
for 10 randomly selected shifts.

d) Based on past sales, a shoe manufacturer considers the mean shoe size of women to be 7.50. The
manufacturer would like to test if this is still the case.

Answer 1

a) The null hypothesis ( H₀ ) and the alternative hypothesis (H_a ) are as follows:

Where ,   is the population mean of the total number of hours spend per week by the students.

Because the phrase "more than" include > inequality in the alternative hypothesis.

c) Here we want to test the population proportion of emergency calls are less than (5/24) = 0.21

Let P denote the population proportion.

H₀ : P = 0.21

H_a : P < 0.21

d) Here mnufacturer want to test whether the mean mean shoe size of women to be 7.50.