a) A conservationist is interested in knowing whether polar bears in the wild have lower rates of reproduction than polar bears in zoos. He measures the number of cubs produced per female during the peak reproductive years, between 1 5 and 30 years of age, in zoos (nl = 24, XI = 19.1, SI = 2.3) and in a wild Alaskan population (n2 = 1 8, X2 = 1 6.3, s2 = 4. 1). This measure of reproductive rate is normally distributed and is assumed to have the same variance in both populations. What is the 95% confidence interval for the difference between means?
b) Before doing the study above, the researcher had reason to believe that the reproductive rate in wild polar bears is lower than in captive polar bears. Do a right-tailed test, at alpha = 0.05, of Ho: meanI - mean.2 = o. State whether you accept or reject Ho, and give the approximate probability of getting this t* value given that Ho is true.