Mary Bartel, an auditor for a large credit card company, knows that, on average, the monthly balance of any given customer is $112, and the standard deviation is $56.
In a sample of 25 observations from a normal distribution with mean 98.6 and standard deviation 17.2
In a normal distribution with mean 375 and standard deviation 48, how large a sample must be taken so that the probability will be at least 0.95 that the sample mean fails between 370 and 380?
In a normal distribution with mean 56 and standard deviation 21, how large a sample must be taken so that there will be at least a 90 percent chance that its mean is greater than 52?
In a sample of 16 observations from a normal distribution with a mean of 150 and a variance of 256, what is
In a sample of 19 observations from a normal distribution with mean 18 and standard deviation 4.8
Food Place, a chain of 145 supermarkets, has been bought out by a larger nationwide supermarket chain.
Davis Aircraft Co. is developing a new wing de-icer system, which it has installed on 30 commercial airliners.
Sara Gordon is heading a fund - raising drive for Milford College. She wishes to concentrate on the current tenth-reunion class, and hopes to get contributions from 36 percent of the 250 members of that class.
Seventy data clerks at the Department of Motor Vehicles make an average of 18 errors per day, normally distributed with a standard deviation of 4.