The ballistic coefficient is a measure of body’s ability to overcome air resistance in flight. That parameter is inversely proportional to the deceleration of a flying body and is very important for bullets. The ballistic coefficient was measured for the bullets of two versions of 9 mm Makarov cartridges, PM and PMM (which is a later and modified version). Sample bullets are chosen randomly.

Find a 95% two-sided confidence interval for the mean difference in the ballistic coefficient.

12.93 12.89 13.13 13.11 12.81 12.83 13.11 12.67 12.85 12.99 13.05 12.75 13.08 13.17 13.16 12.64 PMM 13.88 13.93 13.96 13.65 13.97 13.70 13.54 13.97 13.76 13.52 13.98 13.61 13.65 13.96 PM