) In a study of the effects of caffeine on alertness, 32subjects were randomly assigned to four groups. These groups wereC1: wait-list control (no treatment), C2: placebo control, E1:experimental group 1 (mild caffeine treatment) and E2: experimentalgroups 2 (high caffeine treatment). Several subjects were not ableto complete the study, reducing the group n’s to 7, 5, 6, and 3,respectively. The dependent variable scores were performance scoreson a visual-motor task requiring alertness. The results are asfollows:
| C1 | C2 | E1 | E2 |
| 18 | 20 | 25 | 32 |
| 16 | 18 | 22 | 26 |
| 15 | 15 | 19 | 20 |
| 14 | 12 | 17 | |
| 13 | 10 | 14 | |
| 12 | | 11 | |
| 10 | | | |
Do the results indicate a significant difference betweentreatment groups? State the null hypothesis, Fcritical, η2, and useScheffe’s test to determine which treatment conditions differ inthe event of rejecting the null hypothesis. Conclude with a summaryappropriate for publication.
