TABLE 12-3
A computer used by a 24-hour banking service is supposed to randomly assign each transaction to one of 5 memory locations. A check at the end of a day's transactions gave the counts shown in the table to each of the 5 memory locations, along with the number of reported errors.
The bank manager wanted to test whether the proportion of errors in transactions assigned to each of the 5 memory locations differ.
-Referring to Table 12-3, the degrees of freedom of the test statistic is
A) 4
B) 8
C) 10
D) 448

Question

TABLE 12-3
A computer used by a 24-hour banking service is supposed to randomly assign each transaction to one of 5 memory locations. A check at the end of a day's transactions gave the counts shown in the table to each of the 5 memory locations, along with the number of reported errors.
  The bank manager wanted to test whether the proportion of errors in transactions assigned to each of the 5 memory locations differ.
-Referring to Table 12-3, the degrees of freedom of the test statistic is
A) 4 
B) 8 
C) 10 
D) 448

Quizplus · Accepted Answer

The degrees of freedom for the test statistic is the smaller of the sample sizes minus 1. In this case, the sample sizes are 5 and 10, so the degrees of freedom is 4.

TABLE 12-3 A Computer Used by a 24-Hour Banking Service Is Supposed