The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took these 100 customers to check out was...

The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took these 100 customers to check out was 3.0 minutes. It is known that the standard deviation of the population of checkout times is one minute.With a .95 probability, the sample mean will provide a margin of error of