Question 1 The significance level of a test is A A threshold for how rare our outcome must be before we call it evidence against the null hypothesis. B Specified before we carry out the test. C The probability of rejecting the null hypothesis, given that it is true. D All of the above.The 95% confidence interval for (pr 1 pl) is calculated to be (-3.31. -2.12}. We should decide to fail to reject the null hypothesis that the means are equal. \fIf the p-ualue is 0.5 and the level of significance (alpha, a i is [1.05 in a hypothesis test for a mean then we fail to reject the null hypothesis. Suppose the null hypothesis is that the means in two groups are the same, and the alternative is that they are different {not equal}. The test statistics, : was calculated to be 2.25. and the sample size was 20. We should decide to reject the null hypothesis at level, .i' a = 0.5. A small p-value (close to zero) indicates that we should reject the null hypothesis) An advantage of the Wilcoxon-Mann-Whitney test is that A It makes parametric assumptions. B It takes into account the data values, not only their order It does not require the normality assumption