An Anatomy Teacher Hypothesizes That the Final Grades in Her $10 \% \mathrm {~A}$

An anatomy teacher hypothesizes that the final grades in her class are distributed as $10 \% \mathrm {~A}$ 's, $23 \%$ $B ^ { \prime } s , 45 \% { } ^ { \prime \prime }$ s, $14 \%$ D's, and $8 \% F ^ { \prime } s$ . What is the critical value if at the end of the semester she has the $\begin{array} { l l l l l l } & \text { A } & \text { B } & \text { C } & \text { D } & \text { F } \\ \text { following grades? Use } \alpha = 0.05 . & 6 & 14 & 22 & 8 & 4 \end{array}$

A) 9.236
B) 7.779
C) 11.070
D) 9.488