In a study of student behavior, a school psychologist randomly sampled four students from each of five classes. He then gave each student one of four different tasks to perform and recorded the time,...

In a study of student behavior, a school psychologist randomly sampled four students from each of five classes. He then gave each student one of four different tasks to perform and recorded the time, in seconds, necessary to complete the assigned task. The data from the study are listed in Table 14.17. Using classes as blocks use the Friedman test to determine whether there is a difference in tasks. Use a level of significance of 0.10. Explain your results.