Statistics
posted by Joshua on .
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.

Formula:
CI98 = mean + or  z (sd/√n)
mean = 150; sd = 20; n = 36
Find z using a ztable to represent 98% confidence.
I'll let you take it from here. 
what is answer

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.