13.22 Bilingualism. Not only does speaking two languages have many practical benefits in this globalized world, but there is also growing evidence that it appears to help with brain functioning as we age. In one study, 80 participants were divided equally among 4 groups: younger adult bilinguals, older adult bilinguals, younger adult monolinguals, and older adult monolinguals.15 Each participant was asked to complete a series of color-shape task-switching tests. For our analysis, we’ll focus on the total reaction time (in microseconds) for these experiments. The shorter the reaction time, the better.

  1. (a) Make a table giving the sample size, mean, and standard deviation for each group. Is it reasonable to pool the variances?

  2. (b) Generate a histogram for each of the groups. Can we feel confident that the sample means are approximately Normal? Explain your answer.