Problem 2: Background Information: There is some evidence that "young blood" might improve the health, both physically and cognitively, of elderly people (or mice). In several studies?, old mice were randomly assigned to receive blood plasma from either a young mouse or another old mouse. Researchers then measured the number of minutes each of the old mice was able to run on a treadmill. a) (2 points) If we wish to estimate the difference in the mean length of time on the treadmill between those mice getting young blood and those mice getting old blood, what is the parameter of interest? Define using the appropriate notation. b) (2 points) If the mean length of time on the treadmill for the mice getting young blood was 56.76 minutes and for the mice getting old blood was 34.69 minutes, calculate the best point estimate of the parameter of interest. Use appropriate notation and report your answer with two decimal places