Question: Nile.com, a relatively new online shopping site, makes deliveries of a large number of products to its customers. It is known that 87% of all the orders it receives from its customers are delivered on time. Let be the proportion of orders in a random sample of 250 that are delivered on time. Find the probability that the value of will be

a) Calculate the mean and standard deviation of the sampling distribution of p.

b) Show that the sample size is large enough for the sampling distribution of p to be approximately normally distributed.

c) Find the probability that the sample proportion of orders delivered on time is .9 or higher.