Marketing analysts have determined that a particular adverti

Marketing analysts have determined that a particular advertising campaign should make at least 20% of the adult population aware of the advertised product. After a recent campaign, 400 adults were asked whether or not they had seen the ad and were aware of the new product.

            a.   What is the standard error of p¯?

            b.   What is the probability that the sample proportion will be less than 15%?

            c.   What is the probability that the sample proportion will be between 21.25% and 16.25%?

            d.   What is the probability that the sample proportion will be more than 22.5%?

Solution