Let x be a random variable that represents the amount of a r

Let x be a random variable that represents the amount of a randomly selected monthly cell phone bill. We know that x has a normal distribution with a mean of µ = $70.00 and a standard deviation of = $10. What is the probability that the mean amount of sixteen cell phone bills taken at random is between $67.50 and $72.50?

Solution

mean = 70

std dev = 10

we have to find 67,50<p>72,50