Please help

a) You wish to determine if there are differences in the locations of the data for the two samples below, State your preferred statistical procedure, what assumptions would have to be met, how you would test those assumptions, and what procedure('s) you would follow if the assumptions were not met. (3 marks) 20 30 40 50 60 70 80 90 100 20 30 40 50 60 70 80 90 100 b) In a population of spawning salmon, the average size of fish is 6 kg with a standard deviation of 1:4 kg. A bird of prey won't attack fish less than 4 kg but can't handle anything over 6.5 kg. What proportion of the salmon are potential prey for the bird? Assume the weights of salmon are normally distributed. (2 marks) c) You capture 10 garter snakes at random as they emerge from a hibernation den. The average length of the snakes in your sample is 42 cm with a standard deviation of 6 cm. What are the 95% confidence limits for the mean length of snakes in the den? Assume snake length is normally distributed. (3 marks) d) in a double-blind clinical study, 200 volunteers are randomly assigned to one of two treatments: 100 receive an experimental vaccine against the common cold; the other 100 receive a placebo. In the vaccinated group, 24 individuals report catching a cold during the following 3 months; in the placebo group, 40 report catching a cold. For vaccinated individuals, what is the relative risk of developing a cold compared with unvaccinated individuals? What is the odds ratio? (2 marks)