Aveterinarian does research on the causes of enteroliths, stones that develop in the colon of horses. she suspects that feeding alfalfa might be a cause. to investigate that suspicion, she selects five horses that are known to have enteroliths and compares the number of flakes of alfalfa they have eaten over a month with the number of flakes eaten by five horses free of enteroliths. if she calculates a two-sample confidence interval by hand for the difference in the mean number of flakes fed to horses with and without enteroliths the degrees of freedom she should use are:

10.
8.
4.
5.

8

Step-by-step explanation:

The degree of freedom for t-distribution of testing the differnce between the two population mean is given by :-

, where = Size of first sample.

= Size of second sample.

As per given ,

Veterinarian selects five horses that are known to have enteroliths and compares the number of flakes of alfalfa they have eaten over a month with the number of flakes eaten by five horses free of enteroliths.

i.e. and

Now , If she calculates a two-sample confidence interval by hand for the difference in the mean number of flakes fed to horses with and without enteroliths the degrees of freedom she should use are

Hence, the correct answer is 8.

correct answers below: