Many Junior High School Students Drink Colas on a Daily

Multiple Choice

Many junior high school students drink colas on a daily basis. A researcher is interested in testing the effects of cola ingestion on academic performance (AP) for girls in the ninth grade. One thousand ninth-grade girls are the subjects. They are grouped according to the number of colas they drink each day (low, medium, and high) . The researcher concluded that cola ingestion had an effect on academic performance. What statistical procedure did the researchers probably use?

A) z-test
B) Independent groups t-test
C) Paired t-test
D) ANOVA