Answer: The experiment lacks random experiment and no statistical report to back findings
Explanation: The experiment lacks random assignment, there should be a control group and experimental group in this research which should be randomly picked (giving every participant chance of being selected).
His conclusion depicts that the other groups were not really involved. However, the conclusion would have looked right, if he had given statistical report whether the television programme had an influence on the outcome (aggressive behaviour) on the two groups, preferably using the Paired sample T-test.