Randomly selected nonfatal occupational injuries and illnesses are categorized, according to the day of the week that they first occured, and the results are listed below. Use a 0.05 significance level to test the claim that such injuries and illnesses occur with equal frequency on the different days of the week. Please show your work and justify your answer.
Day MON TUE WED THUR FRI
Number 23 23 21 20 18