The U.S. Department of Health and Human Services compiles statistics on the consumption of alcohol.
An investigator decides to look at the role of age in determining alcohol use. She requests data on the amount of drinking done by three different age groups: 16- to 20-year-olds, 21- to 25-year-olds, and 26-year-olds. The results come in, and a statistician conducts an analysis of variance.
The is that there is no difference between the population means (in other words, there is no treatment effect).
The is that at least one of the population means is different from another (in other words, there is an effect of at least one of the treatments).
Note: The term "treatment effect" is used even when there is not actually a treatment.
The age group is .
The treatments (16- to 20-year-olds, 21- to 25-year-olds, and 26-year-olds) are .
Which of the following might contribute to between-treatments variance? Check all that apply.
Individual differences in the number of drinks per drinking binge
Systematic differences in drinking frequency by age group
Systematic differences in drinking preference by age group