Detrermining standard error of the mean

Reference no: EM1316261

In order to estimate the average electric usage per month, a sample of n = 81 houses was selected, and the electric usage was determined.

(a) Assume a population standard deviation of 450-kilowatt hours. Determine the standard error of the mean. _______________

(b) With a probability of 0.95, what is the size of the margin of error? _______________

(c) If the sample mean is 1858-kilowatt hours, what is the 95% confidence interval estimate of the population mean? _______________________

Reference no: EM1316261

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