Answer:
A. Increase sample size
Step-by-step explanation:
From the formula for estimating the confidence level interval for the mean:
X - Z × s/sqrt n where; X = sample mean; Z = z value corresponding to 95%;
s = standard deviation and n = sample size
It is evident from the equation that the confidence interval for the mean is inversely proportional to the sample size (n), hence increasing the sample size will result in a reduced interval width.
