A Firm Is Studying the Effect of Work Shift and Parts

Multiple Choice

A firm is studying the effect of work shift and parts supplier on its defect rate (dependent variable is defects per 1000) . The resulting ANOVA results are shown below (some information is missing) . $$\begin{array} { | l | c | c | c | c | c | } \hline \text { Source } & \text { Sum of Squares } & d f & \text { Mean Square } & F & \text { P-Value } \\\hline \text { Shift } & 704.07 & 2 & 352.04 & 11.93 & 0.001 \\\hline \text { Supplier } & 19.6 & & 9.8 & 0.33 & 0.72 \\\hline \text { Shift*Supplier } & 430.75 & 4 & 107.69 & 3.65 & 0.014 \\\hline \text { Error } & 1062.05 & 36 & 29.5 & & \\\hline \text { Total } & 2216.47 & 44 & & & \\\hline\end{array}$$ How many suppliers were there?

A) 1
B) 2
C) 3
D) 4