Find the sample size necessary to find the proportions within 2% at the 90% confidence level if no preliminary estimate of proportions is known.
A.) Not enough info
B.) 1693
C.) 1691
D.) 1692
Find the sample size necessary to find the proportions within 2% at the 90% confidence level...
The sample size needed to estimate the difference between two population proportions to within a margin of error m with a significance level of α can be found as follows. In the expression m=z∗p1(1−p1)n1+p2(1−p2)n2−−−−−−−−−−−−−−−−−−−−√ we replace both n1 and n2 by n (assuming that both samples have the same size) and replace each of p1, and p2, by 0.5 (because their values are not known). Then we solve for n, and get n=(z∗)22E2. Finally, increase the value of n to...
(1 point) The sample size needed to estimate the difference between two population proportions to within a margin of error E with a significance level of α can be found as follows. In the expression E=z∗p1(1−p1)n1+p2(1−p2)n2‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾√ we replace both n1 and n2 by n (assuming that both samples have the same size) and replace each of p1, and p2, by 0.5 (because their values are not known). Then we solve for n, and get n=(z∗)22E2. Finally, increase the value of...
find the critical value fir confidence level c=90% and sample size n=8
Use the expression in the accompanying discussion of sample size to find the size of each sample if you want to estimate the difference between proportions of men and women who own smartphones. Assume that you want 90% confidence that your error is no more than 0.04. i Click the icon to view the discussion of sample size. The sample should include (Type whole numbers.) men and women. i Sample size discussion - X The sample size needed to estimate...
Answers only is fine! Find the critical value zc necessary to form a confidence interval at the level of confidence shown below. c=0.92 Find the margin of error for the given values of c, σ, and n. c = 0.95, σ =2.4, n = 8.1 Level of Confidence. zc 90% 1.645 95% 1.96 99% 2.575 Construct the confidence interval for the population mean μ. c=0.98, x=9.5, σ=0.3, and n= 52 Construct the confidence interval for the population mean μ. c=0.95, x=16.7, σ=6.0, and n=...
In this exercise, we examine the effect of the confidence level on determining the sample size needed. Find the sample size needed to give a margin of error within plus or minus 4 with 99% confidence. With 95% confidence. With 90% confidence. Assume that we use σ=35 as our estimate of the standard deviation in each case. Round your answers up to the nearest integer. 99% n= 95%n= 90% n=
What is the minimal sample size needed for a 90% confidence interval to have a maximal margin of error of 0.05 if there is no preliminary estimate for p?
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 0.01 with 90% confidence if (a) she uses a previous estimate of 0.34? (b) she does not use any prior estimates?
An IQ test is designed so that the mean is 100 and the standard deviation is 13 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 90% confidence that the sample mean is within 4 IQ points of the true mean. Assume that σ=13 and determine the required sample size using technology. Then determine if this is a reasonable sample size for...
A researcher wishes to estimate, with 90% confidence, the population proportion of motor vehicle fatalities that were caused by alcohol-impaired driving. His estimate must be accurate within 2% of the population 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 25% of motor vehicle fatalities that were caused by alcohol-impaired driving. (c) Compare the results from parts (a) and (b).