A town has 500 real estate agents. The mean value of the properties sold in a year by these agents is $500,000, and the standard deviation is $250,000. A random sample of 100 agents is selected, and the value of the properties they sold in a year is recorded. a. What is the standard error of the sample mean? b. What is the probability that the sample mean exceeds $513,000? c. What is the probability that the sample mean exceeds $489,000? d. What is the probability that the sample mean is between $483,000 and $505,000? Click on the icon to view the standard normal table. a. The standard error of the sample mean is| (Round to the nearest integer as needed.) b. The probability that the sample mean exceeds $513,000 is (Round to four decimal places as needed.) c. The probability that the sample mean exceeds $489,000 is (Round to four decimal places as needed