A soccer ball manufacturer wants to estimate the mean circumference of soccer balls within 0.05 in. (a) Determine the minimum sample size required to construct a 90% confidence interval for the population mean. Assume the population standard deviation is 0.20 in. (b) Repeat part (a) using a population standard deviation of 0.40 in. Which standard deviation requires a larger sample size? Explain.
Home
A soccer ball manufacturer wants to estimate the mean circumference of soccer balls within 0.05 in. (a) Determine the minimum sample size required to construct a 90% confidence interval for the population mean. Assume the population standard deviation is 0.20 in. (b) Repeat part (a) using a population standard deviation of 0.40 in. Which standard deviation requires a larger sample size? Explain.
feel free to call us +800.241.0630 russ@russellcoder.com
Related Articles

Find the margin of error for the given values of c, sigma, and n.
russellc, , Statistics, 0
c = 0.95. a = 2.1, n = 36 Answer 0.686

A credit card company claims that the mean credit card debt for individuals is greater than $ 5000. You want to test this claim. You find that a random sample of 30 cardholders has a mean credit card balance of $ 5202 and a standard deviation of $ 600. At alpha equals 0.01, can you support the claim? Complete parts (a) through (e) below. Assume the population is normally distributed.
russellc, , Statistics, 0
see excel spreadsheet. This your answer


You are given the sample mean and the population standard deviation. Use this information to construct the 90% and 95% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals. If convenient, use technology to construct the confidence intervals. A random sample of 60 home theater systems has a mean price of $140. Assume the population standard deviation is $15.40 Construct a 90% confidence interval for the population mean. The 90% confidence interval is (nothing,nothing).
russellc, , Statistics, 0 
Use the confidence interval to find the margin of error and the sample mean.
russellc, , Statistics, 0
(0.264,0.460) The margin of error is 0.098.The sample mean is .3620.



Find the critical value tc for the confidence level c equals=0.90 and sample size n equals=18 LOADING… Click the icon to view the tdistribution table. Use a tdistribution table to look up the tvalue using the level of confidence c and the degrees of freedom nminus−1. The level of confidence c equals=0.90 is given.
russellc, , Statistics, 0