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Having done poorly on a particular exam in a junior high school, 22 students decide to write the exam again to try and improve their mark. Results are given in the following table. Student n Average Standard deviation Attempt 1 (A1) 22 60 3.8 Attempt 2 (A2) 22 65 4.5 Difference (d = 22 5.0 3.1 1 - A2) (a) Find an 80% 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 No, since the interval contains 0. 0 Yes, since the interval is completely below 0. 0 Yes, since the interval contains 0. Check eclass.srv.ualberta.ca A clinic compared healthy dogs it owned with healthy pets brought to clinic to be neutered. The summary statistics for blood cholesterol levels (milligrams deciliter of blood) appear in the following table: Types n Average Standard deviation Pets (P) 31 193 63.1 Clinic (C) 31 181 47.4 Difference (d : P 31 12.0 53.9 _ C) (a) Find a 98% 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? 0 Yes, since the interval contains 0. O Yes, since the interval is completely above 0. O No, since the interval contains 0. O No, since the interval is completely above 0. Check Beclass.srv.ualberta.ca Question 18 Tries remaining: 1 Marked out of 2.00 \\V Flag question A mechanical engineer is studying bonding issues with the thermal protection tiles on the Space Shuttle. He wants to see whether there is any difference in the bonding strength between 5 different compounds. Tiles are randomly assigned to one of the 5 compounds so that each compound is tested on 29 tiles. Each tile is coated with its assigned compound and bonded to a surface. After a period of time, pull-tests are performed to determine the amount of force needed to break the bond. What is the distribution of the test statistic when the null hypothesis is true? ltisa(n) t-distribution : with df:4. A v Last saved at 13:44:15 Save Progress Previous page Next page eclass.srv.ualberta.ca Check