download.file("http://www.openintro.org/stat/data/ames.RData", destfile = "ames.RData") load("ames.RData") names(ames)

#On your own

# .Using the following function (which was downloaded with the data set), # plot all intervals. What proportion of your confidence intervals include # the true population mean? Is this proportion exactly equal to the # confidence level? If not, explain why. par(mfrow = c(1, 1)) plot_ci(lower_vector, upper_vector, mean(population))

# .Pick a confidence level of your choosing, provided it is not 95%. # What is the appropriate critical value?

# .Calculate 50 confidence intervals at the confidence level you chose # in the previous question. You do not need to obtain new samples, # simply calculate new intervals based on the sample means and # standard deviations you have already collected. Using the plot_ci function, plot all intervals and calculate the proportion of intervals that include the true population mean. How does this percentage compare to the confidence level selected for the intervals?

#This is a product of OpenIntro that is released under a [Creative Commons Attribution-ShareAlike 3.0 Unported](http://creativecommons.org/licenses/by-sa/3.0). This lab was written for OpenIntro by Andrew Bray and Mine ?etinkaya-Rundel.