A Biology Professor Claims That, on the Average $15 \%$ Of Her Students Get a Grade Of

Multiple Choice

A biology professor claims that, on the average, $15 \%$ of her students get a grade of $A$ , $25 \%$ get a B, $40 \%$ get a C , $10 \%$ get a D, and $10 \%$ get an $\mathrm { F }$ . The grades of a random sample of 131 students were recorded. The following table presents the results.
$\begin{array}{c|lllll}\text { Grade } & 1 & 2 & 3 & 4 & 5 \\\hline \text { Observed } & 13 & 21 & 73 & 11 & 13\end{array}$

What is the value of $\chi ^ { 2 }$ ?

A) 14.902
B) 9.488
C) 11.143
D) 16.873