A researcher wishes to estimate, with 99 % confidence, the population proportion of adults who think Congress is doing a good or excellent job. Her estimate must be accurate within 4% of the true proportion. (a) No preliminary estimate is available. Find the minimum sample size needed. (b) Find the minimum sample size needed, using a prior study that found that 42% of the respondents said they think Congress is doing a good or excellent job. (c) Compare the results from parts (a) and (b). (a) What is the minimum sample size needed assuming that no prior information is available? (Round up to the nearest whole number as needed.) (b) What is the minimum sample size needed using a prior study that found that 42% of the respondents said they think Congress is doing a good or excellent job? (Round up to the nearest whole number as needed.) sibl (c) How do the results from (a) and (b) compare? arce A. Having an estimate of the population proportion has no effect on the minimum sample size needed. for B. Having an estimate of the population proportion raises the minimum sample size needed. imed OC. Having an estimate of the population proportion reduces the minimum sample size needed.

A programmer plans to develop a new software system. In planning for the operating system that he will use, he needs to estimate the percentage of computers that use a new operating system. How many computers must be surveyed in order to be 90% confident that his estimate is in error by no more than five percentage points? Complete parts (a) through (c) below. a) Assume that nothing is known about the percentage of computers with new operating systems. n=0 (Round up to the nearest integer.) b) Assume that a recent survey suggests that about 95% of computers use a new operating system. n=0 (Round up to the nearest integer.) c) Does the additional survey information from part (b) have much of an effect on the sample size that is required? O A. No, using the additional survey information from part (b) does not change the sample size. O B. No, using the additional survey information from part (b) only slightly increases the sample size. OC. Yes, using the additional survey information from…

A researcher wishes to​ estimate, with 90% ​confidence, the population proportion of adults who think Congress is doing a good or excellent job. Her estimate must be accurate within 2% of the true proportion. ​(A) No preliminary estimate is available. Find the minimum sample size needed. (Round up to the nearest whole number as​needed.)

Determine the sample size needed to be 99% confident the population proportion estimate is within 3% of the true proportion.  There is no prior information regarding values for p and q.