Chapter 9: Hypothesis Testing

Chapter 9: Hypothesis Testing Section 2: Tests Involving the Mean (Large Samples) Example A sports biologist claimed that female distance runners tend to be taller on the average than women in general, who have an average height of 64 inches. To study

this, she obtained a random sample of 40 female distance runners and recorded their heights with the following results: x = 65.6 inches and s = 3.3 inches. Using these results, test the claim at the 5% level of significance. Example A bus company advertised a mean time of 150 minutes for a trip between two cities.

A consumer group had reason to believe that the mean times was more than 150 minutes. A sample of 40 trips showed a mean of 153 minutes and a standard deviation of 7.5 minutes. Test the claim at the 5% level of significance. Example The owner of an artesian well-drilling company suspected that, for a large tract

of development land, the average depth of water below the surface was less than 500 feet. A sample of 32 wells gave a mean depth of 486 feet and a standard deviation of 53 feet. At the 1% level of significance, is the owners suspicion justified?