For each word problem, use a solution sheet to solve the hypothesis test problem. Go to the reference for the chi-square solution sheet. Round expected frequency to two decimal places.
Airline companies are interested in the consistency of the number of babies on each flight, so that they have adequate safety equipment. They are also interested in the variation of the number of babies. Suppose that an airline executive believes the average number of babies on flights is six with a variance of nine at most. The airline conducts a survey. The results of the 18 flights surveyed give a sample average of 6.4 with a sample standard deviation of 3.9. Conduct a hypothesis test of the airline executive’s belief.
OpenStax Introductory Statistics 2e, 11.6 Test of a Single Variance, exercise 30