A 2016 study found that U.S. employees work an average of 475 minutes a day when working on site at their job. A student suspects that U.S. employees work less now due to changes in workforce expectations. In a random sample of 30 U.S. employees, the mean amount of time they work per day is 470 minutes. Assume the population standard deviation is 28.6 minutes. At the 5% significance level, is there sufficient evidence that the current mean amount of time that U.S. employees work on-site per day is less than the prior average. (15 points) a. State the hypotheses. b. Calculate the standardized test statistic. Show the calculation. c. Find the P-value. Round to 3 decimal places. d. Sketch the P-value for the hypothesis test. e. Make decision about the hypotheses and answer the research question in the