Part 1

In the study of marine adaptations of reptiles, previous work has indicated that Galapagos Island marine iguanas can hold their breath underwater a mean of 38.0 minutes. The ocean temperatures in the Galapagos have risen over the past decade which forces the iguanas to dive deeper for food more regularly. Due to this, an oceanographer claims that the mean time these iguanas can hold their breath underwater has increased. To test this claim, the oceanographer studied 20 randomly selected, Galapagos Island marine iguanas. In the study, the sample mean time the iguanas could hold their breath underwater was 38.7 minutes with a sample standard deviation of 4.2 minutes. Assume that the population of amounts of time Galapagos Island marine iguanas can hold their breath underwater is approximately normally distributed. Complete the parts below to perform a hypothesis test to see if there is enough evidence, at the 0.10 level of significance, to support that u, the mean time Galapagos Island marine iguanas can hold their breath underwater, is now more than 38.0 minutes. (a) State the null hypothesis /, and the alternative hypothesis /, that you would use for the test. X Ho: 0 H: I 020 0=0 0+0 X 5 ? (b) Perform a hypothesis test. The test statistic has a / distribution (so the test is a "t test"). Here is some other information to help you with your test. . to.10 is the value that cuts off an area of 0.10 in the right tail. . The value of the test statistic is given by t = = x u