The аmоunt оf time thаt а drive-thrоugh bank teller spends on a customer is a random variable with a mean image006554cbe3b.gif minutes and a standard deviation image007554cbe3b.gif minutes. If a random sample of 25 customers is observed, find the probability that their mean time at the teller’s window is more than 3.5 minutes. Assume that the distribution is approximately normal. Tables.pdf