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21. Suppose you were hired to conduct a study to find out which of two first year courses students prefer. In your study, the same group of students are given an opportunity to attend course I and then course 2. They rated one course and then rated the other The ratings are given on a scale of 1 (horrible) to 5 (amazing). Which type of test would be the best to compare these ratings? (a) Independent two-sample Z-test. (b) Dependent t-test of the differences. c) One-sample t-test. (d) Independent two-sample t-test. 22. The correlation between two scores on tests was found to be exactly 1. Which of the following would not be true, regarding the corresponding scatterplot? (a) The best fitting line would have a positive gradient. b) Every point would lie along a perfect straight line, with no deviations at all c) All of the above are true. (d) The slope of the best fitting line would be 1. 23. If you take all samples of a particular size from a particular population, find the mean of each sample, and then plot the means, what have you created? (a) Sample distribution. b) Significance level. Sampling distribution. d) Population distribution