Sami Schmitt Believes That the Number of Cars Arriving at His

Multiple Choice

Sami Schmitt believes that the number of cars arriving at his Scrub and Shine Car Wash follows a Poisson distribution.He collected a random sample and constructed the following frequency distribution to test his hypothesis. $$\begin{array} { | l | l | l | l | l | l | l | } \hline \text { Cars per 15-rrirute iriterval } & 0 & 1 & 2 & 3 & 4 & \geq 5 \\\hline \text { Observed frequency } & 5 & 15&17 & 12& 10 & 8 \\\hline\end{array}$$

Using $\alpha$ = 0.05, the critical value of chi-square for this goodness-of-fit test is ____.

A) 9.49
B) 7.81
C) 7.78
D) 11.07
E) 12.77