A Biology Professor Claimed That the Proportions of Grades in His

Essay

A biology professor claimed that the proportions of grades in his classes are the same. A sample of 100 students showed the following frequencies. $$\begin{array} { | l | c | c | c | c | c | } \hline \text { Grade } & \text { A } & \text { B } & \text { C } & \text { D } & \text { F } \\\hline \text { Frequency } & 14 & 23 & 27 & 26 & 10 \\\hline\end{array}$$ Determine the rejection region at the 5% significance level.