Research Is Conducted Regarding the Average Age at Retirement for Four

Multiple Choice

Research is conducted regarding the average age at retirement for four career groups.To test whether there is a relationship between age of retirement and career in these groups,700 employees,recently retired,are randomly selected.The resulting data are displayed in the contingency table below. $\begin{array}{|l|c|c|c|c|c|}&&\text { age at retirement}\\\hline career& 50-55 & 56-60 & 61-65 & \text { Over } 65 & \text { Total } \\\hline \text { Attorney } & 10 & 40 & 75 & 40 & 165 \\\hline \begin{array}{l}\text { College } \\\text { Professor }\end{array} & 5 & 30 & 80 & 60 & 175 \\\hline \text { Secretary } & 21 & 45 & 63 & 49 & 178 \\\hline \text { Store Clerk } & 18 & 44 & 70 & 50 & 182 \\\hline \text { Total } & 54 & 159 & 288 & 199 & 700 \\\hline\end{array}$ How many degrees of freedom are there for the chi-square test statistic?

A) 12
B) 9
C) 16
D) 20
E) 25