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.

Question

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.

Quizplus · Accepted Answer

The test statistic is calculated by comparing the observed frequencies with the expected frequencies under the Poisson distribution. The value of 2.89 is the result of this comparison, indicating how well the observed data fits the Poisson model.

The Owner of a Car Wash Wants to See If