A population has a mean of 400 and a standard deviation of 90. Suppose a sample of size 100 is selected and I is used to estimate µ. Use z-table. a. What is the probability that the sample mean will...

Extracted text: A population has a mean of 400 and a standard deviation of 90. Suppose a sample of size 100 is selected and I is used to estimate µ. Use z-table. a. What is the probability that the sample mean will be within +/- 9 of the population mean (to 4 decimals)? (Round z value in intermediate calculations to 2 decimal places.) b. What is the probability that the sample mean will be within +/- 10 of the population mean (to 4 decimals)? (Round z value in intermediate calculations to 2 decimal places.)