D Question 19 8 pts Salaries of 25 college graduates who took a statistics course in college have a mean of $84,120 and a standard deviation of $1,048. Construct a 95% confidence interval for estimating the population mean. Enter the lower bound of the confidence interval. (Round your answer to nearest whole dollar.) D Question 20 7 pts John wishes to estimate the population mean salary of college graduates who took a statistics course in college. How many college graduates must he survey? Assume that the population standard deviation is known to be $1,483, and he wants to be 99% confident that the sample mean is within $106 of the true population mean. D Question 21 16 pts A manufacturer considers his production process to be out of control when defects exceed 3.5%. In a random sample of 113 items, the defect rate is 9.3% but the manager claims that this is only a sample fluctuation and production is not really out of control. At the 5% level of significance, use the critical value method to test the manager's claim. Enter the smallest critical value. (Round your answer to nearest thousandth.)