We need an estimate of the mean acreage of Canadian farms. We plan to measure the acreage for a random sample of 100 farms.

We need an estimate of the mean acreage of Canadian farms. We plan to measure the acreage for a random sample of 100 farms. Results from an earlier study suggest that 200 acres is a reasonable guess for the standard deviation of farm size. Find the probability that the sample mean acreage falls within 20 acres of the population mean acreage.