The Internal Revenue Service is studying contributions to charity. The mean calculated from a random sample of 36 returns is $150. Assume that the population standard deviation is known and equal to $20. Construct a 98 percent confidence interval for the population mean.

Answer 1

Formula:

CI98 = mean + or - z (sd/√n)

mean = 150; sd = 20; n = 36
Find z using a z-table to represent 98% confidence.

I'll let you take it from here.

Answer 2

what is answer

Answer 3

The Internal Revenue Service is studying contributions to charity. The mean calculated from a random sample of 36 returns is $150. Assume that the population standard deviation is known and equal to $20. Construct a 98 percent confidence interval for the population mean.