Use the sample data from Exercise 7 "Wristwatch Accuracy" and construct a 95% confidence interval estimate of σ.
Students of the author collected data measuring the accuracy of wristwatches. The times (sec) below show the discrepancy between the real time and the time indicated on the wristwatch. Negative values correspond to watches that are running ahead of the actual time. The data appear to be from a normally distributed population. Construct a 95% confidence interval estimate of the mean discrepancy for the population of wristwatches.
-85 325 20 305 -93 15 282 27 555 570 -241 36