2. In-class activity Without using any measuring device, each student should draw a line believed to be 3 in.

long and another line that is 3 cm long. Then use rulers to measure and record the lengths of the lines drawn. Find the means and standard deviations of the two sets of lengths. Use the sample data to construct a confidence interval for the length of the line estimated to be 3 in., then do the same for the length of the line

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Bootstrap Resampling The bootstrap method can be used to construct confidence intervals for situations in which traditional methods cannot (or should not) be used. For example, the following sample of 10 values was randomly selected from a population with a distribution that is very far from normal, so any methods requiring a normal distribution should not be used.

2.9 564.2 1.4 4.7 67.6 4.8 51.3 3.6 18.0 3.6 If we want to use the above sample data for the construction of a confidence interval estimate of the population mean m, we note that the sample is small, and there is an outlier.

380 Chapter 7 Estimates and Sample Sizes estimated to be 3 cm. Do the confidence interval limits actually contain the correct length? Compare the results. Do the estimates of the 3-in. line appear to be more accurate than those for the 3-cm line?