In a 2020 survey of 80 graduate economists and 110 graduate programmers, it was found that the graduate economists had a mean starting salary of 48,100 with a standard deviation of 7,200, while the graduate programmers had a mean starting salary of 52,900 with a standard deviation of 5,300. a) Find a point estimate for the difference in average starting salaries for graduate economists and programmers. [5 marks] b) Let m1 be the population mean starting salary for the graduate economists and let m2 be the population mean salary for the graduate programmers. Find a 96% confidence interval for m1 m2. Assume the standard deviations given are the population standard deviations. [5 marks] c) Based on the interval in part (b), would you be comfortable saying that the mean starting salary for graduate economists is less than that for graduate programmers? Justify your answer. [5 marks]