In 1994, the chief executive officers of the major tobacco companies testified before a U.S. Senate subcommittee. One of the accusations made was that tobacco firm’s added nicotine to their cigarettes, which made them even more addictive to smokers. Company scientists argued that the amount of nicotine in cigarettes depended completely on the size of the tobacco leaf: During poor growing seasons, the tobacco leaves would be smaller than in normal or good growing seasons. However, because the amount of nicotine in a leaf is a fixed quantity, smaller leaves would result in cigarettes having more nicotine (because a greater fraction of the leaf would be used to make a cigarette). To examine the issue, a university chemist took random samples of tobacco leaves that were grown in greenhouses where the amount of water was allowed to vary. Three different groups of tobacco leaves were grown. Group 1 leaves were grown with about an average season’s rainfall.

Group 2 leaves were given about 67% of group 1’s water, and group 3 leaves were given 33% of group 1’s water. The size of the leaf (in grams) and the amount of nicotine in each leaf were measured.

a. Test to determine whether the leaf sizes differ between the three groups.

b. Test to determine whether the amounts of nicotine differ in the three groups.