Researchers Raluca Barac and Ellen Bialystok (2012) conducted a study in which they compared the language skills of 104 six-year-old children who were in one of four groups. Some children spoke only English. Others were bilingual, speaking English along with Chinese, French, or Spanish. The children completed the Peabody Picture Vocabulary Test (PPVT) as a measure of their vocabulary. An excerpt from the results section of the published journal article follows: “A oneway ANOVA on PPVT scores showed a main effect of language group, F (3, 100) = 8.27, p < .0001. Post hoc [tests] indicated that the monolingual children and the Spanish-English bilingual children outperformed the other two bilingual groups who did not differ from each other.” (Note: When p values are tiny, as in this case, researchers report that they are less than some small value, rather than reporting the exact p value, such as 0.00000038.)

a. What is the independent variable, what kind of variable is it, and what are its levels? What is the dependent variable and what kind of variable is it?

b. How do we know that this finding is statistically significant?

c. Why was the one-way ANOVA not sufficient to draw a conclusion from these data?

d. Summarize this finding in your own words.