In: Math
Exhibit: Checking Accounts.
A bank has kept records of the checking balances of its customers and determined that the average daily balance of its customers is $300 with a standard deviation of $56. A random sample of 200 checking accounts is selected. You are interested in calculating the following probabilities below.
For all answers below, do not round intermediate steps if any and round your final solution to 4 decimal places.
(1)Assuming that the population of the checking account balances is normally distributed, what is the probability that a randomly selected account has a balance of more than $305?
(2)What is the probability that the mean balance for the selected sample is above $295?
(3)What is the probability that the mean balance for the selected sample is between $302 and $304?
Another one:
A biology class with 114 students recently had an exam. The mean exam score was 82 and the standard deviation of the exam score was 12.
(1)What is the probability that a random sample of 37 exams has an average score below 84?