Researchers are studying two different designs of computer keyboards, J and K, to investigate the effectiveness of the design on the speed of data entry. The researchers believe there is a tendency for people entering data with keyboard J to have faster entry times compared with people entering data with keyboard K. Using the same set of data for entry, the researchers randomly assigned
people to keyboard J and
people to keyboard K and recorded the number of seconds each person took to enter the data. The following dotplots show the observed entry times for the two keyboards.