Which of the following is not an advantage of pooling sample variances? choose the correct answer below. a. we often know that sigma1equalssigma2. b. confidence intervals are a little narrower. c. hypothesis tests have more power. d. the number of degrees of freedom is a little higher.

(a) we often know that

Step-by-step explanation:

The sampling variance is pooled when there is assumption that the population variance are equal which is not an advantage. So   will have no advantage of pooling sample variances   is given in option (A) so option (A) will be the right answer

Option A - we often know that

Step-by-step explanation:

To find : Which of the following is NOT an advantage of pooling sample variances?

Solution :

Pooled variance is defined as a method for estimating variance of several different populations when the mean of each population may be different, but one may assume that the variance of each population is the same.

So,

The sampling variance is pooled when there is assumption that the population variance are equal which is not an advantage.

i.e. we often know that

Therefore, option A is correct.

answer: 457.14

step-by-step explanation:

205 - 45 = 160

160 / .35 = 457.142857