Question

A telemarketer found that there was a 1% chance of a sale from his phone solicitations. Find the probability of getting 5 or more sales for 1000 telephone calls. Note: Use a normal approximation to the binomial distribution.

Answer 1

Solution:

We are given:

We have to first find the mean and standard deviation of the given data.

Let x be the number of sales and we are required to find:

Using the continuity correction factor, we have to find:

Now using the z-score formula, we have:

Now using the standard normal table, we have:

Therefore, the probability of getting 5 or more sales for 1000 telephone calls is 0.9599