Leak Rate. LDS wants to be sure that the leak rate (in cubic cen- timeters per second) of transmission oil coolers (TOCs) meets the established specification limits. A random sample of 50 TOCs is tested, and the leak rates are recorded in the data file tocs.xlsx, under the tab TOC. Estimate the variance in leak rate with a 95% confidence level. Before you construct the confidence interval make sure that you check the assumption of normality