The Owner of a Car Wash Wants to See If

Multiple Choice

The owner of a car wash wants to see if the arrival rate of cars follows a Poisson distribution.In order to test the assumption of a Poisson distribution, a random sample of 150 ten-minute intervals was taken.You are given the following observed frequencies: $\begin{array} { l c }\text {Number of Cars Arriving }&\text { Frequency}\\\text { in a 10-Minute Interval }\\ 0 & 3 \\ 1 & 10 \\ 2 & 15 \\ 3 & 23 \\ 4 & 30 \\ 5 & 24 \\ 6 & 20 \\ 7 & 13 \\ 8 & 8 \\ 9 \text { or more } & 4 \\ & 150 \end{array}$
The calculated value for the test statistic equals

A) 3.11.
B) .18.
C) 1.72.
D) 2.89.