A human resource manager for a large company takes a random sample of 60 employees from the company database. Based on the sample she calculates a 95% confidence interval for the mean time of employment for all employees to be 8.7 to 15.2 years.Which of the following will provide a more informative (i.e., narrower) confidence interval than the 95% confidence interval? Check all that apply. Using a 90% confidence level (instead of 95%) Using a 99% confidence level (instead of 95%) Using a sample size of 40 employees (instead of 60) Using a sample size of 90 employees (instead of 60)

A study was conducted to estimate μ, the mean number of weekly hours that U.S. adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage time of 8.5 hours and that from prior studies, the population standard deviation is assumed to be σ = 3.6 hours. The 95% confidence interval for the mean, μ, is (7.7, 9.3).Which of the following will provide a more informative (i.e., narrower) confidence interval than the 95% confidence interval? Check all that apply. Using a sample of size 400 (instead of 81) Using a sample of size 36 (instead of 81) Using a different sample of size 81 Using a 90% level of confidence (instead of 95%) Using a 99% level of confidence (instead of 95%)

Examine the following statements and then select the one statement that is correct.Group of answer choicesA wider confidence interval means less confidence in the estimate (all other things being equal).A narrower confidence interval is always better than a wider confidence interval.For a 95% confidence interval for a population mean, there is a 95% chance that the confidence interval includes the sample mean.The width of a confidence interval is affected by both the sampling error and the required level of confidence.

A student was asked to find a 95% confidence interval for widget width using data from a random sample of size n = 27. Which of the following is a correct interpretation of the interval 13.1 < μ < 25.9?Check all that are correct.There is a 95% chance that the mean of the population is between 13.1 and 25.9.With 95% confidence, the mean width of all widgets is between 13.1 and 25.9.With 95% confidence, the mean width of a randomly selected widget will be between 13.1 and 25.9.There is a 95% chance that the mean of a sample of 27 widgets will be between 13.1 and 25.9.The mean width of all widgets is between 13.1 and 25.9, 95% of the time. We know this is true because the mean of our sample is between 13.1 and 25.9.

The same 53 participants were also asked how many years that had worked in paid employment. Based on the sample data, a 95% confidence interval for underlying mean years of paid employment is (13.4, 17.4).A student tried using the confidence interval calculator to construct the confidence interval from the same sample data and got (14.4, 16.4) because they entered the wrong sample size.What sample size did they enter?

Which statement regarding confidence intervals is TRUE?Group of answer choicesA 95% confidence interval produced from different data to a 99% confidence interval will likely be narrower.A 95% confidence interval produced from the same data as a 99% confidence interval will likely be wider.A 95% confidence interval produced from the same data as a 99% confidence interval will likely be narrower.A specific 95% confidence interval is the probability that a population parameter of interest falls within a specified range.