An environmentalist wants to find out the fraction of oil tankers that have spills each month. In an earlier study, the population proportion was estimated to be 0.270.27.   How large a sample would be required in order to estimate the fraction of oil tankers that have spills each month at the 98%98% confidence level with an error of at most 0.030.03? Round your answer up to the next integer.

An economist needs to estimate the proportion of residents of Sebastian that have earned a college degree. Determine the most conservative estimate of the sample size required to limit the margin of error to within 0.025 of the population proportion for a 96% confidence interval.Round the solution up to the nearest whole number.n=

Suppose we wish to study the average income of Cactus Club customers, so we plan to conduct a research project with a 95% confidence level. We need our range of error (E) to be no greater than $500. Based on our past experience, we estimate the sample standard deviation to be $5,000. What sample size do you need in order to conduct the research? Select one: a. 372 b. 784 c. 824 d. 385 e. 196

At one large college, 660 out of the 1500 students surveyed said they plan to take another science class.Find the 95% confidence interval for the proportion of students that said they plan to take another science class.

A researcher wishes to estimate the proportion of college students who cheat on exams. A poll of 480 college students showed that 23​% of them​ had, or intended​ to, cheat on examinations. Find the​ 95% confidence interval for the population proportion. Round to four decimal places.

A random sample of 800 home owners in a particular city found 208 home owners who had a swimming pool in their backyard. Find a 95% confidence interval for the true percent of home owners in this city who have a swimming pool in their backyard. Express your results to the nearest hundredth of a percent. Answer: ☐ t to %

The Bureau of Alcohol, Tobacco, and Firearms (BATF) has been concerned about lead levels in California wines. In a previous testing of wine specimens, lead levels ranging from 51 to 750 parts per billion were recorded. How many wine specimens should be tested if the BATF wishes to estimate the true mean lead level for California wines to within 10 parts per billion with 95% confidence? (Round your answer up to the nearest whole number.)

Researchers wants to determine if low-fat diets or low-carb diets are more effective for weight loss. Suppose 100 people were placed on a low-fat diet and at the end of 3 months the mean weight loss was 10.5 lbs witha standard deviation of 12.5 lbs. There were another 100 people placed on a low-carb diet and at the end of 3 months the mean weight loss was 16.5 lbs with a standard deviation of 10.2 lbs. Does mean weight lossdiffer between the two diets? What are the hypotheses??