15. If other factors are held constant, what is the effect of decreasing the sample size? a. It will increase the estimated standard error and increase the likelihood of rejecting H0 b. It will increase the estimated standard error and decrease the likelihood of rejecting H0 c. It will decrease the estimated standard error and increase the likelihood of rejecting H0 d. It will decrease the estimated standard error and decrease the likelihood of rejecting H0

c. It will decrease the estimated standard error and increase the likelihood of rejecting H0

Step-by-step explanation:

Given that a sample size is decreased after keeping other factors constant.

In hypothesis testing if sample size is decreased while others are kept constant we have the following

The margin of error = critical value * std dev/sqrt n

In other words, the margin of error is inversely proportional to square root of sample size.

So if n increases, margin of error decreases, making confidence interval narrower.

This gives more chance for rejecting null hypothesis.

Hence correct answer would be

c. It will decrease the estimated standard error and increase the likelihood of rejecting H0