A) A random sample of 35 business students required an average of 50.7 minutes to complete a statistics exam. Assume that the population standard deviation to complete the exam was 10.4 minutes. Construct the 99% confidence interval to estimate the average minutes to complete the exam. Find the lower and upper confidence level.

B) According to a money report by a government institution, 18-to-20-year-old college students have an average credit card balance of $ 569. A researcher wants to find out if this number is lower now and collects data for a random sample of 40 college students. Their average credit card debt was found to be $553 with a sample standard deviation of $68.42. Use =. .Complete parts a through c.

1- Determine the null and alternative hypotheses. 2- Determine the appropriate critical value. () 3- Calculate the appropriate test statistic. 4- State the conclusion.