A study will be carried out to estimate the percentage of citizens of a city who are in favor of having fluoridated water. How large should the sample be if you want to have at least 95% confidence that the estimate is within 0.015 of the true percentage? From previous studies it is estimated that the proportion of the population that is in favor of having fluoridated water is 0.6.
Important note: Use 3 rounded decimals in the critical value.
Answer using 4 decimals.
A study will be carried out to estimate the percentage of citizens of a city who...
A survey is to be carried out to estimate the proportion of all registered voters in California who favor legalizing marijuana. How many people should be included in a random sample to estimate the proportion to within 0.05 with 95% confidence?
A previous random sample of 4000 U.S. citizens yielded 2250 who are in favor of gun control legislation. How many citizens would need to be sampled for a 95% confidence interval to estimate the true proportion within 2%
You wish to take a same of citizens in a particular city to determine the percentage of people who are diabetic. A previous survey of 2500 people shows that 215 people are diabetic. How large a sample size will you need to construct a 90% confidence interval for the proportion of citizens who are diabetic, with a margin of error no more than 5%.
a. Assume that a sample is used to estimate a population proportion p. Find the 95% confidence interval for a sample of size 198 with 42 successes. Enter your answer as an open-interval (i.e., parentheses) using decimals (not percents) accurate to three decimal places. 95% C.I. = b. A political candidate has asked you to conduct a poll to determine what percentage of people support her. If the candidate only wants a 0.5% margin of error at a 99% confidence...
The Centers for Disease Control reported the percentage of people 18 years of age and older who smoke (CDC website, December 14, 2014). Suppose that a study designed to collect new data on smokers and nonsmokers uses a preliminary estimate of the proportion who smoke of 27. a. How large a sample should be taken to estimate the proportion of smokers in the population with a margin of error of .02 (rounded up to the next whole number)? Use 95%...
A survey of 548 citizens found that 363 of them favor a new bill introduced by the city. we want to find a 95% confidence interval for the true proportion of the population who favor the bill. what is the lower limit of the interval? ( Round to 3 decimal digits)
Assume an approximate normal distrihution. IS. A random sample of 12 eniployees of the Wlergate Carpet Company wed an average contribution of $8.00 to the American Cancer Socicty, with a landard deviation of $1.25, Construct u 90% wnfidence interva: for the average contribution by all employces of the Watergate Carpet Company to the American Cancer Society. Assume the contribuions to hc?pproxi- matcly normally distributed. Suction 8.5 16. (a) A random sample of 200 voters from Salem, Virginia, is selected and...
A study is to be made to estimate the proportion of residents of a certain city and its suburbs who favor the construction of a nuclear power plant near the city. How large a sample is needed if one wishes to be at least 90% confident that the estimate is within 0.07 of the true proportion of residents who favor the construction of the nuclear power plant? Click here to view page 1 of the standard normal distribution table. Click...
A politician wants to estimate the proportion of citizens who "vote for him." What sample size should be obtained if he wants to be within 2 percentage points with 95% confidence if he uses an estimate of 14% obtained from a poll? Round up your answer. Use the z table from the canvas module 5.
The Centers for Disease Control reported the percentage of people 18 years of age and older who smoke (CDC website, December 14, 2014). Suppose that a study designed to collect new data on smokers and nonsmokers uses a preliminary estimate of the proportion who smoke of .35. a. How large a sample should be taken to estimate the proportion of smokers in the population with a margin of error of .02 (to the nearest whole number)? Use 95% confidence. b....