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 0.03 with 95% confidence if (a) she uses a previous estimate of 0.42? (b) she does not use any prior estimates? Click the icon to view the table of critical values. (a) n= (Round up to the nearest integer.) (Round up to the nearest integer.) Table of critical values (b) n = Critical Value, z Level of Confidence, (1 - a)· 100% Area in Each Tail, 90% 0.05 1645 95% 0.025 1.96 99% 0.005 2.575 Print Done

The head of a computer science department is interested in estimating the proportion of students entering the department who will choose the new computer engineering option. A preliminary sample indicates that the proportion will be around 0.35. Therefore, what size sample should the department head take if she wants to be 95% confident that the estimate is within 0.10 of the true proportion?

For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding.In a survey of 1000 large corporations, 246 said that, given a choice between a job candidate who smokes and an equally qualified nonsmoker, the nonsmoker would get the job. (a) Let p represent the proportion of all corporations preferring a nonsmoking candidate. Find a point estimate for p. (Round your answer to four decimal places.)(b) Find a 0.95 confidence interval for p. (Round your answers to three decimal places.) lower limit       upper limit       What is the margin of error based on a 95% confidence interval? (Round your answer to three decimal places.)

You may need to use the appropriate appendix table or technology to answer this question. Of 290 female registered voters surveyed, 119 indicated they were planning to vote for the incumbent president. Of 425 male registered voters, 157 indicated they were planning to vote for the incumbent president. (a) Compute the test statistic. (Use female male. Round your answer to three decimal places.) (b) At a = 0.01, test to see if there is a significant difference between the population proportions of females and males who plan to vote for the incumbent president. (Use the p-value approach.) Calculate the p-value. (Round your answer to three decimal places.) p-value = What is your conclusion? O Do not reject Ho. We can conclude that there is a significant difference between the two poplation proportions. O Do not reject Ho. We cannot conclude that there is a significant difference between the two population proportions. O Reject Ho. We cannot conclude that there is a significant difference…

On average, a sample of n = 36 scores will provide a better estimate of the population mean than a sample of n = 49 scores from the same population.

What percentage of your campus student body is female? Let p be the proportion of women students on your campus.

For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding.In a marketing survey, a random sample of 982 supermarket shoppers revealed that 262 always stock up on an item when they find that item at a real bargain price. (a) Let p represent the proportion of all supermarket shoppers who always stock up on an item when they find a real bargain. Find a point estimate for p. (Round your answer to four decimal places.)(b) Find a 95% confidence interval for p. (Round your answers to three decimal places.) lower limit       upper limit

For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding.In a marketing survey, a random sample of 992 supermarket shoppers revealed that 274 always stock up on an item when they find that item at a real bargain price. (a) Let p represent the proportion of all supermarket shoppers who always stock up on an item when they find a real bargain. Find a point estimate for p. (Enter a number. Round your answer to four decimal places.) (b) Find a 95% confidence interval for p. (For each answer, enter a number. Round your answers to three decimal places.)lower limit     upper limit     Give a brief explanation of the meaning of the interval. We are 95% confident that the true proportion of shoppers who stock up on bargains falls within this interval.We are 5% confident that the true proportion of shoppers who stock up on bargains falls above this interval.     We are 5% confident that the true proportion of shoppers who…

Using the following scenario,  calculate the value of the point estimate. What proportion of students are willing to report cheating by other students? A student project put this question to an SRS of 229 undergraduates at a large university: "You witness two students cheating on a quiz. Do you go to the professor?" Only 25 answered "yes".    Round your answer to two decimal places.