A researcher conducts a study on the effects of task difficulty (easy, hard) and presence of others (no one else present, 5 other people present) on task performance. Task performance is assessed by measuring how many Sudoku puzzles a participant is able to complete in 30 minutes. Below are the mean numbers of correct responses for each of the resulting conditions in the study. Easy Difficult No one else present 7 9 Five others present 14 2 The results from this study indicate there is .