A psychologist was interested in the effects of time of day on critical thinking. Participants were randomly assigned to one of three groups (Morning, Afternoon, or Night) and given a measure to test...

A psychologist was interested in the effects of time of day on critical thinking. Participants were randomly assigned to one of three groups (Morning, Afternoon, or Night) and given a measure to test for the number of answers correct on a critical thinking ability test. The following data were obtained from the study.

Morning                                 Afternoon                              Night

4                                                3                                               8

3                                                1                                               4

5                                                3                                               6

4                                                1                                               6

What is the appropriate conclusion from this study (a = .05)?