Chapter 17, Problem 33E

To determine

To Explain: The researcher needs to suspect that the real success rate has been manipulated.

Explanation of Solution

The concern is that a sale is likely to be 12 per cent, and the total amount of calls made is 200, and the total number of sales made is 10.

Therefore, the probability that researcher made sale is $\frac{10}{200}=0.05$

Nothing is similar to the real chance, as it makes a selling of 0.05, which is very poor. Therefore, he may be suspected of being misled.