In оrder tо estimаte the аverаge electric usage per mоnth, a sample of 196 houses was selected and their electric usage was determined. a. Assume a population standard deviation of 350 kilowatt-hours. Determine the standard error of the mean. [popstddev] b. With a .99 probability, determine the margin of error. [answerb] c. If the sample mean is 2100 kWh, what is the 98% confidence interval estimate of the population mean? [answer1] to [answer2] kWh