1. For a student's research study, a group of 60 participants were randomly assigned between four different groups. After seeing the number of participants assigned to each group (shown below) the student's supervisor is concerned that the random assignment procedure may have been biased and that the participants were not distributed equivalently among the groups. Conduct a one-way chi-square test (a = .05) to determine if the supervisor's concerns are valid.

Group 1 Group 2 Group 3 Group 4

18 9 20 13

No use of excel please. Avoid handwritten explanations and show all calculations.