you would like to know how long american scuba-divers can stay underwater. you heard that the average number of minutes american scuba-divers can dive without coming to the surface equals 65 minutes. you do not believe that is true and decide to conduct a test. your null hypothesis is that the population mean equals 65. your alternative hypothesis is that the population mean differs from 65. you question 40 randomly selected american scuba-divers and discover that they can stay underwater for only 64 minutes. the standard deviation is 5 minutes. assume a = significance level = 0.05. (a) find test statistic. (b) do you reject your null hypothesis? (c) interpret your results