The increased availability of light materials with high strength has revolutionized the design and manufacture of golf clubs, particularly drivers. Clubs with hollow heads and very thin faces can result in much longer tee shots, especially for players of modest skills. This is due partly to the "spring- like effect" that the thin face imparts to the ball. Firing a golf ball at the head of the club and measuring the ratio of the out- going velocity of the ball to the incoming velocity can quan- tify this spring-like effect. The ratio of velocities is called the coefficient of restitution of the club. An experiment was per- formed in which 15 drivers produced by a particular club maker were selected at random and their coefficients of resti- tution measured. In the experiment the golf balls were fired from an air cannon so that the incoming velocity and spin rate of the ball could be precisely controlled. It is of in- terest to determine if there is evidence (with a = 0.05) to sup- port a claim that the mean coefficient of restitution exceeds 0.82. The observations follow:

0.8411 0.8191 0.8182 0.8125 0.8750
0.8580 0.8532 0.8483 0.8276 0.7983
0.8042 0.8730 0.8282 0.8359 0.8660

In performing the appropriate hypothesis test, what is the value of the test statistic? Calculate up to 5 decimal places. Answer with 2 decimal places.