the goodman tire and rubber company periodically tests its tires for tread wear under simulated road conditions. to study and control the manufacturing process, 20 samples, each containing three radial tires, were chosen from different shifts over several days of operation, with the following results. tread wear measurements are in hundredths of an inch. sample tread wear 1 31 42 28 2 26 18 35 3 25 30 34 4 17 25 21 5 38 29 35 6 41 42 36 7 21 17 29 8 32 26 28 9 41 34 33 10 29 17 30 11 26 31 40 12 23 19 25 13 17 24 32 14 43 35 17 15 18 25 29 16 30 42 31 17 28 36 32 18 40 29 31 19 18 29 28 20 22 34 26
