1. Justin wants to know whether a commonly prescribeddrug does improve the attention span of students with attention deficitdisorder (ADD). He knows that the mean attention span for students with...

1.


Justin wants to know whether a commonly prescribed drug does improve the attention span of students with attention deficit disorder (ADD). He knows that the mean attention span for students with ADD who are not taking the drug is 2.3 minutes long. His sample of 12 students taking the drug yielded a mean of 4.6 minutes. Justin can find no information regarding σx , so he calculated s2x =1.96.