Question 12 (2 points) A physician is evaluating a new diet for her patients with a family history of heart disease. To test the effectiveness of this diet, 16 patients are placed on the diet for 6 months. Their triglyceride levels are measured before and after the study, and the physician wants to know if the measurements have changed. Which of the following statements is true: Mean n Std Std error deviation of mean Pre- 138.44 16 29.040 7.260 triglyceride Post- 124.38 16 29.412 7.353 triglyceride Paired t-test data: dietatudYSth and dietstudetq4 t = 1.2, at - 15, p-vaiue = 0.2437 alternative hypothesis: true dirterence in means is not equal to O 95 percent condence interval: -1D.91541 39.04041 sample estimates: an at the ditterences 14.0625 0 The pre and post treatment values are independent of each other. 0 The pre and post treatment values cannot be validly compared because they are not independent of each other. 0 Post treatment values are randomly sampled from pre treatment values. 0 This is a paired design with 2 repeated observations on each patient. uestion 13 (2 points) Researchers sampled fish from a lake and measured the lengths (mm) of all individuals of two species, bream and perch. They were interested in testing whether there was a difference in the mean lengths of the two species in the lake. Based on the output below, what would be the most correct statement about the tests carried out? Mean n Std Std error deviation of mean Bream 531.00 6 309.60 126.39 Perch 154.82 11 78.76 23.75 Two Sample t-test data: length]. by species t - 3.9019, c: - 15, p-vaiue . 0.001416 alternative hypothesis: true dirzerence in means is not equal to 0 95 percent contidence interval: 170.6882 581.6755 sample est inmates: mean in areas Bream mean in croup Perch 531.0000 154.8182 ODD MD lD Ieng'M 400 Belch Tic Sample t-test 2m data: lengthi by species t - 2.9251, 61 - 5.356, p-vaiue - 0.03024 alternative hypothesis: true difference in means is not equal to O 95 percent contidence interval: 52.08779 700.27534 sample estimates: mean in group Bream mean in group Perch 531.0000 151.8182 Imam Perch SID-Gin O The Pvalues for the two versions of the test are the same. 0 A ttest is not appropriate for testing the null hypothesis of no difference in mean length between the species. 0 The equal variance ttest is the appropriate version to use for these data. O The unequal variances t-test (Welch's test) is the appropriate version to use for these data