Question: The benefits of foreign language study: Members of a high school language club believe that study of a foreign language improves a student’s command of English. From school records, they obtain the scores on an English achievement test given to all seniors. The mean score of seniors who studied a foreign language for at least two years is much higher than the mean score of seniors who studied no foreign language. These data are not good evidence that language study strengthens English skills. Identify explanatory and response variables in this study. Then explain what lurking variable prevents the conclusion that language study improves students’ English scores.