Question

The following information was obtained from matched samples. The daily production rates for a sample of workers before and after a training program are shown below. Worker Before After 1 20 22 2 25 23 3 23 27 4 23 20 5 22 21 6 20 19 7 17 18 8 20 21 9 19 18 Refer to Exhibit 3. Assuming that the population of differences has a normal distribution, what is the degrees of freedom for the t distribution for matched samples test of a hypothesis about the difference between the two population means (population mean before training - population mean after training) ? A. 10 B. 8 C. 15 D. None of the above

Answer 1

As the case is matched samples so the number of degrees of freedom for testing difference of means is

where n is the size of both the samples

Here n=9,

So number of degrees of freedom is

Option B is correct