Question 12 It is believed that animals living in northern regions have shorter appendages than animals living in southern regions. Tries remaining: Random samples of birds were selected from each group and wing lengths for birds (in millimeters) were measured. 3 The following table gives summary statistics. Marked out of 3.00 Region n Average Standard deviation Flag Northern (N) 31 118.5 1.8 question Southern (S) 31 120.3 3.8 Difference (d = N - S) 31 -1.8 1.7 (a) Find a 98% confidence interval for the mean difference of wing lengths of birds between the northern regions and the southern regions. (Round your answers to 4 decimal places, if needed.) (b) Based on this confidence interval, is there enough evidence to support the belief? O No, since the interval is completely below 0. O No, since the interval contains 0. O Yes, since the interval contains 0. O Yes, since the interval is completely below 0. CheckQuestion 13 A clinic compared healthy dogs it owned with healthy pets brought to clinic to be neutered. The summary statistics for Tries remaining: blood cholesterol levels (milligrams deciliter of blood) appear in the following table: 3 Marked out of Types n Average Standard deviation 3.00 Pets (P) 61 192 69.6 Flag Clinic (C) 61 182 41.6 question Difference (d = P - C) 61 10.0 49.5 (a) Find an 80% confidence interval for the difference in mean blood cholesterol levels dogs brought to the clinic (P) and dogs owned by the clinic (C). (Round your answers to 4 decimal places, if needed.) (b) Based on this confidence interval, can we conclude there is some differences in mean blood cholesterol levels between the two groups? O Yes, since the interval contains 0. O Yes, since the interval is completely above 0. O No, since the interval is completely above 0. O No, since the interval contains 0. CheckQuestion 16 Having done poorly on a particular exam in a junior high school, 22 students decide to write the exam again to try and Tries remaining: improve their mark. Results are given in the following table. 3 Marked out of Student n Average Standard deviation 3.00 Attempt 1 (A1) 22 52 3.1 Flag Attempt 2 (A2) 22 57 4.8 question Difference (d = A1 - A2) 22 -5.0 2.4 (a) Find a 95% confidence interval for the difference in mean scores between attempt 1 and attempt 2. (Round your answers to 4 decimal places, if needed.) (b) Based on this confidence interval, can we conclude there is a difference in mean scores between attempt 1 and attempt 2? O No, since the interval is completely below 0. O Yes, since the interval is completely below 0. O No, since the interval contains 0. O Yes, since the interval contains 0. Check