Suppose that the number of customers who enter a supermarket each hour is normally distributed with a mean of 520 and a standard deviation of 210. The supermarket is open 12 hours per day. What is the probability that the total number of customers who enter the supermarket in one day is greater than 7400? (Hint: Calculate the average hourly number of customers necessary to exceed 7400 in one 12-hour day.)

Birthweight at a hospital were reported to have a mean of 3668 grams (g) and a standard deviation of     511 g. These birthweights are normally distributed.  Find the probability that a single baby's birth weight was less than 4000 g.

The average amount of money spent for lunch per person in the college cafeteria is $5.99 and the standard deviation is $2.1. Suppose that 49 randomly selected lunch patrons are observed. Assume the distribution of money spent is normal, and round all answers to 4 decimal places where possible. For the group of 49 patrons, find the probability that the average lunch cost is between $5.77 and $6.08.

The average amount of money spent for lunch per person in the college cafeteria is $6.24 and the standard deviation is $2.05. Suppose that 6 randomly selected lunch patrons are observed. Assume the distribution of money spent is normal, and round all answers to 4 decimal places where possible.For the group of 6 patrons, find the probability that the average lunch cost is between $6.2647 and $7.3532.

Suppose collection of all quiz marks of a class of students is normally distributed with a mean of 7 and a standard deviation of 1. Calculate the probability that a student will receive a mark less than 5.

Assume that adults have IQ scores that are normally distributed with a mean of95.4 and a standard deviation of 16.6. Find the probability that a randomly selected adult has an IQ greater than 118.1 The probability that a randomly selected adult from this group has an IQ greater than 118.1 is what?

5. The mean birth weight for babies born one month early is 2630 grams. Assume that the population has a standard deviation of 220 grams. Sketch the distribution of birth weights (in grams) of children born one month early. Calculate probability of a child born one month early with a birth weight between 2100 grams and 2900 grams. Find the weight which corresponds to the top 25% of birth weights for babies born one month early.

The length of human pregnancies from conception to birth is approximately Normal with a mean  length of 266 days and a standard deviation of 16 days.  What is the probability that the average pregnancy length for 7 randomly chosen women exceeds 270 days?

A technician can service an air conditioner in an average of one hour and fifteen minutes with a standard deviation of 20 minutes. (Assume the time is normally distributed). What is the probability that the technician can fix ten air conditioners in less than twelve hours?