In: Statistics and Probability
1) A sample of 25 Brand W 40-gallon water heaters was found to have a mean life of 12 years with a standard deviation of s = 2 years. Construct a 95% confidence interval to estimate the population mean life of these water heaters, to 4 decimal places. (Note that σ is unknown)
2) A 95% confidence interval was constructed to estimate the population proportion of New Yorkers who are on some type of government assistance based on a sample of size n = 872. The interval was found to be (0.16, 0.28). Which statement correctly interprets the confidence interval?
3) Indicate which situation would produce a less precise (wider) confidence interval;
A) A 90% confidence level.
B) A 95% confidence level.
4) True or False? An unbiased statistic to estimate a population characteristic will produce a value that is always close to the true population value.