Question

Advertisers contract with internet service providers and search engines to place ads on websites. They pay a fee based on the number of potential customers who click on their ad. Unfortunately, click fraud—the practice of someone clicking on an ad solely for the purpose of driving up advertising revenue—has become a problem. Business week reports that 40 percent of advertisers claim they have been a victim of click fraud. Suppose a simple random sample of 360 advertisers will be taken to learn more about how they are affected by this practice. (Round your answers to four decimal places.) (a) What is the probability that the sample proportion will be within ±0.04 of the population proportion experiencing click fraud? Incorrect: Your answer is incorrect. (b) What is the probability that the sample proportion will be greater than 0.45?

Answer 1

Answer:

Given that:

Advertisers contact with internet service provides and search engines to place ads on websites.

a)

Percentage of advertisers who claim that they been a victim of click fraud = 40%

S o the population proportion p = 0.40

Size of the random sample n = 380 advertisers

The expected value of the sample proportion is

Standard error of is :

Probability that the sample proportion will be within   0.04 of the population proportion is :

  

z- value corresponding to is :

At = 0.36 , we have

  

At = 0.44 , we have

  

So the required probability is :

  

  

b)

Probability that the sample proportion will be greater than 0.45 is p(> 0.45)

z- value corresponding to is :

  

At   = 0.45, we have

  

So the required probability is :