What is the smallest sample size needed to guarantee that the results of a study conducted to find the proportion of US toddlers who have a good diet will be accurate within 3% at the 95% confidence level?(a) A previous study found that 21% of US toddlers have a good diet. b) No preliminary estimate is available.

II. The Dean of Arts and Sciences wants to evaluate student opinions on online courses. A small survey of 13 students asked them to rate their experiences online from 1(Bad) to 5(Great). 5 5 5 5 4 4 4 4 4 4 2 2 1 a) Based on the sample data above, what is the population mean estimator value for student experience? b) Construct a confidence interval with a 99% confidence for this data.)

In a sample of 95 recommendations, it is found that 56% of them made money. Determine the upper bound of the 95% confidence interval for the proportion of recommendations that make money?

2)   A random sample of 120 students at a high school was asked whether they would ask their father or mother for help with a homework assignment in science. A second random sample of 150 different students was asked the same question for an assignment in history. Fifty-four students in the first sample and 72 students in the second sample replied that they turned to their mother rather than their father for help. Construct a 99% confidence interval for the difference of the two proportions and express it as   .   (Round both numbers to the 4th decimal plac

A) What proportion of commercial airline pilots are more than 40 years of age? Suppose an analyst has access to a list of all pilots who are members of the Air Line Pilots Association. If this list is used as a frame for the study, she can randomly select a sample of pilots, contact them, and ascertain their ages. From 89 of these pilots so selected, she learns that 48 are more than 40 years of age. Construct an 85% confidence interval to estimate the population proportion of commercial airline pilots who are more than 40 years of age. B) Suppose you want to estimate the proportion of cars that are sport utility vehicles (SUVs) being driven in Regina at rush hour by standing on the corner of Victoria Avenue and Albert Street and counting SUVs. You believe the figure is no higher than 0.40. If you want the error of the confidence interval to be no greater than 0.03, how many cars should you randomly sample? Use a 90% level of confidence.

Suppose a 90 percent confidence interval to estimate a population proportion was calculated from a sample proportion of 18 percent and a margin of error of 4 percent. What is the width of the confidence interval?

According to some car loan statistics, 44% of Americans are relying on an auto loan to pay for their cars. Assuming this finding to be based on a simple random sample of 1500 Americans, construct and interpret the 95% confidence interval for the population proportion of Americans who have a car loan.

in a poll, 73% of California adults (367 out of 506 surveyed) believe that education is one of the main issues facing California. We want to construct a 90% confidence interval for the true proportion of California adults who believe that education is one of the main issues facing California.-  I need help with finding a 90% confidence interval for the population proportion (I also have to round the answer to three decimal places)

In the Star and Tribune newspaper, there is an article entitled "1 in 8 school buses fail tests." The article says that the overall statewide proportion of school buses that fail safety tests is 9%. However, one bus company has a higher rate of over 12%. Assume that we want a new estimate for the statewide proportion of school buses that fail the safety inspection. How large a sample would you have to take in order to construct a 95% confidence interval estimate for the true proportion of buses that fail the inspection and achieve a margin of error of plus or minus 2%? (your answer should be an integer)

ESPN believed that 30 percent of Sportszone visitors were females. To test this hypothesis, it collected audience profile data at the ESPN SportsZone Web site and found that 36% of the visitors were females. Assume that this sample value was based on a sample of 300 users. Test its hypothesis using 95% confidence level.