11.24 ● ▼ To determine if chocolate milk was as effective as other carbohydrate replacement drinks, nine male cyclists performed an intense workout followed by a drink and a rest period. At the end of the rest period, each cyclist performed an endurance trial in which he exercised until exhausted and time to exhaustion was measured. Each cyclist completed the entire regimen on two different days. On one day the drink provided was chocolate milk and on the other day the drink provided was a carbohydrate replacement drink.

Data consistent with summary quantities appearing in the paper “The Efficacy of Chocolate Milk as a Recovery Aid” (Medicine and Science in Sports and Exercise

[2004]: S126) appear in the table at the bottom of the page. Is there evidence that the mean time to exhaustion is greater after chocolate milk than after carbohydrate replacement drink? Use a significance level of .05. (Hint: See Examples 11.6 and 11.7.)

Time to Exhaustion (minutes)
Cyclist 1 2 3 4 5 6 7 8 9 Chocolate Milk 24.85 50.09 38.30 26.11 36.54 26.14 36.13 47.35 35.08 Carbohydrate Replacement 10.02 29.96 37.40 15.52 9.11 21.58 31.23 22.04 17.02