Twin Sistas Carolina and Michelle of Noh Mommies! Medical Group found that the mean annual earnings of pharmacists in the US are $230,000 and those of pediatricians to be $225,000. Suppose that these results are based on a random sample of 300 pharmacists and 400 pediatricians and that the population standard deviations are $28,000 and $32,000 respectively. a. What is the standardkerror? (3pts.) b_ Construct a 97% confidence interval for the difference between the me annual earnings of pharmacists and pediatricians. (4pts.) 0. Test the claim, using a 5% level of significance, that the mean annual earnings of pharmacists is greater than that of pediatricians. (6pts.)