2. Formulating hypotheses and determining whether a test is one-or two-tailed To identify the correct Z(critical), it is important to determine whether the hypothesis test is one-tailed or two-tailed. The decision between a one- and two-tailed hypothesis is based on the researcher's expectations about the population from which the sample was selected. Many people believe that millennials are having more sex than people during the sexual revolution. You wonder whether the cohort currently in their twenties had sex at an earlier age than older generations. Assume that the the average age of first sexual intercourse is 17.4 years. You obtain a sample that yields a sample mean of X = 15.9 years. Let denote the average age of first sexual intercourse. Formulate your null and research hypotheses by selecting the appropriate values in the dropdown menus that follow. H0 : (H1 : ) The test you conduct is test. Note: A one-tailed test is described as a lower-tailed test if the null hypothesis is rejected for values of the test statistic in the lower tail of its distribution, and it is described as an upper-tailed test if the null hypothesis is rejected for values of the test statistic in