Assume z is a standard normal random variable. Compute the following probabilities.
a. P(1.33 z 1.67)
b. P(1.23 z 1.55)
c. P(z 2.32)
d. P(z 2.08)
e. P(z 1.08)
Question 2
In order to estimate the average electric usage per month, a sample of 196 houses was selected and the electric usage determined.
a. Assume a population standard deviation of 350 kilowatt-hours. Determine the standard error of the mean.
b. With a .95 probability, determine the margin of error.
c. If the sample mean is 2,000 KWH, what is the 95 confidence interval estimate of the population mean?