Exercise 3 (12 marks) To find out whether a new serum will arrest leukemia. 10 mice. all with an advanced stage of the disease, are selected. Five mice receive the treatment and 5 do not. Survival times. in years, from the time the experiment commenced are as follows: Treatment: 2.1 5.3 1.4 4.6 0.9 No Treatment: 1.9 0.5 2.8 3.] 2.7 a) Can the serum be said to be effective? Assume the two populations to be normally distributed. b) Verify your work in part a] with an appropriate confidence interval. (Don't forget to state the appropriate level of confidence) Exercise 4 (8 marks) Using the above data [question 3), the true average lifetime of mice with no treatment is more than 3 months smaller than it is for the mice with treatment? Assume the two populations to be normally distributed with equal variability. Exercise 6 {i 7 marks} Under certain conditions. electrical stimulation of a beef carcass will improve the tenderness of the meat. In one study of this effect. beet carcasses were split in half: one side [half]: was subjected to a brief electrical current and the other side was an untreated control. For each side. a steak was cut and tested in various ways for tenderness. In one test. the experimenter obtained a specimen of connective tissue [collagen] from the steak and determined the temperature at which the tissue would shrink: a tender piece of meat tends to yield a low collagen shrinkage temperature. The data are given in the tollowing table: Collagen Shrinkage Temperature t ' C t Treated Side Control Side 695 3'0 6? 69 ?0.?5 69.5 68.5 69.25 66.?5 6?.?5 68.5 66.5 69.5 63.?5 69 TO 66.?5 66.?5 69 68.5 69.5 69 69 69.?5 "30.5 70.25 63 66.25 69 63.25 a] At the 0.01 level of signicance. test to see it there is a significant difference in the two methods. [to be done by hand. not excel} b] What assumption is necessary to perform the test in part a]? c} Verify your work in part {at by conducting the appropriate condence interval. [Don't forget to state the appropriate level of condence] d] Set up a hypothesis to test if electrical stimulation of a beef carcass will improve the tenderness of the meat. [Set up the hypothesis only. you are not required to carry out the test for part d}. l