A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.040.04 with 9999% confidence if (a) she uses a previous estimate of 0.540.54? (b) she does not use any prior estimates?

(a) The sample size required is 1034.

(b) The sample size required is 1040.

Step-by-step explanation:

The confidence interval for population proportion is:

The margin of error is:

Given:

The critical value of z for 99% confidence level is:

*Use a standard normal table.

(a)

Compute the sample size required if the previous estimate is as follows:

Thus, the sample size required is 1034.

(b)

Compute the sample size required if there was no previous estimate as follows:

Assume that the estimated proportion be 0.50.

Thus, the sample size required is 1040.

$450 is the answer.

step-by-step explanation:

30% of 450 = 135

450-135=315