please answer ALL 3 questions. question 1 has part a&b thank you in advance will give a like ! :)

V We want to conduct a hypothesis test of the claim that for middle-aged adults the population mean of their cholesterol levels is less than 191.8 - 8 mg dL . We choose a random sample of such levels. The sample has a mean of 192.8 - mg dL and a standard deviation of 18.5 - dL For each of the following sampling scenarios, choose an appropriate test statistic for our hypothesis test on the population mean. Then calculate that statistic. Round your answers to two decimal places. (a) The sample has size 110, and it is from a non-normally distributed population with a known standard deviation of 19.3. O = =1 `It is unclear which test statistic to use. X 5 ? (b) The sample has size 13, and it is from a normally distributed population with an unknown standard deviation. It is unclear which test statistic to use. V The mean salary offered to students who are graduating from Coastal State University this year is $24,245, with a standard deviation of $3678. A random sample of 75 Coastal State students graduating this year has been selected. What is the probability that the mean salary offer for these 75 students is $25,000 or more? Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places. X Standard normal value Let Z be a standard normal random variable. Use the calculator provided, or this table, to determine the value of c. P(c