If other factors are held constant, which combination of sample characteristics would produce the narrowest confidence interval for a population mean?
answer
a. large sample size (n) with large variance
b. small sample size (n) with small variance
c. large sample size (n) with small variance
d. small sample size (n) with large variance

The correct option is C) large sample size (n) with small variance.

Step-by-step explanation:

Consider the provided information.

It is given that the other factors are held constant, and we want the narrowest confidence interval for a population mean.

Confidence interval for a population mean is directly proportional to variance and inversely proportional to the sample size.

If we increase the variance, CI will increase. But we want the narrowest CI, so variance should be small.

As CI is inversely proportional to sample size, therefore if we increase the sample size CI will decrease.

Hence, the correct option is C) large sample size (n) with small variance.