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: 
 Number of Cars Arriving in a 10-Minute Interval Frequency 
 0 3 
 1 10 
 2 15 
 3 23 
 4 30 
 5 24 
 6 20 
 7 13 
 8 8 
 9 or more 4 
 150 
 The calculated value for the test statistic equals:_______