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

Question

Quizplus · Accepted Answer

The degrees of freedom for a chi-square test in a contingency table is calculated as (number of rows - 1) * (number of columns - 1). Here, there are 4 career groups (rows) and 4 age categories (columns), so the degrees of freedom is (4-1)*(4-1) = 9.

Research Is Conducted Regarding the Average Age at Retirement for Four