Payne (2001) gave participants a computerized task in which they first see a face and then a picture ...

     21. Payne (2001) gave participants a computerized task in   which they first see a   face   and then a picture of either a gun or a tool. The task was to press one   button   if   it was a tool and a different one if it was a gun. Unknown to the   participants   while   they were doing the study, the faces served as a “prime” (something that   starts   you thinking a particular way); half the time they were of a black person   and   half the time of a white person. Table 2–9 shows the means and standard   deviations   for   reaction times (the time to decide if the picture is of a gun or a tool)   after   either a black or white prime. (In Experiment 2, participants were told to   decide as fast    as   possible.) Explain the results to a person who was never had a course in   statistics.    (Be   sure to explain some specific numbers as well as the general principle of the   mean and standard deviation.)        Table   - Mean Reaction Times (in Milliseconds) in Identifying Guns and Tools in   Experiments 1 and 2       Prime    Black   White   Experiment   1 M SD M SD   •   Gun 423 64 441 73   •   Tool 454 57 446 60   Experiment   2   •   Gun 299 28 295 31   •   Tool 307 29 304 29