A study was made of 147 industrial accidents that required medical attention. Among those accidents, 31 occurred on Monday, 42 on Tuesday, 18 on Wednesday, 25 on Thursday, and 31 on Friday (based on results from "Counted Data CUSUM's," by Lucas, Tecbnometrics, Vol. 27, No. 2). Test the claim that accidents occur with equal proportions on the five workdays. If they are not the same, what factors might explain the differences?