LDS wants to be sure that the leak rate (in cubic centimeters per second) of transmission oil

Question:

LDS wants to be sure that the leak rate (in cubic centimeters per second) of transmission oil coolers (TOCs) meets the established specification limits. A random sample 50 TOCs is tested, and the leak rates are recorded in the data file TOC. Estimate the variance in leak rate with a 95% confidence level (check normality).