An Industrial-Organizational psychologist is investigating the effects of different types of motivation on the performance of clerical tasks. Ten subjects in the “individual motivation” sample are told that they will be rewarded according to how many tasks they successfully complete. Then ten subjects in the “group motivation” sample are told that they will be rewarded based on the average number of tasks completed for the group. The data follows:

Individual: 11, 17, 14, 10, 11, 15, 10, 8, 12, 15

Group: 10, 15, 14, 8, 9, 14, 6, 7, 11, 13

Do the groups differ in terms of performance? Provide a 95% confidence interval for the group difference.