When a company advertises on the Internet, the company pays the operators of search engines each time an ad for the company appears with search results and someone clicks on the link. Click fraud is when a computer program pretending to be a customer clicks on the link. An analysis of 1,400 clicks coming into a company's site during a week identified 220 of these clicks as fraudulent. Complete parts (a) through (c) below.

Show the 95% confidence interval for the population proportion of fraudulent clicks in a form suitable for sharing with a nontechnical audience.

If a company pays the operators of a search engine $4.75 for each click, give a 95% confidence interval for the mean cost per click due to fraud.

The 95% confidence interval for the mean cost is