A research and development engineer is preparing a report for the board of directors on the battery life of a new cell
phone they have produced. At a 95% confidence level, he has found that the battery life is 3.2 ± 1.0 days. He wants to
adjust his findings, so the margin of error is as small as possible. Which of the following will produce the smallest margin
of error?
A. Increase the confidence level to 100%. This will assure that there is no margin of error.
B. Increase the confidence level to 99%.
C. Decrease the confidence level to 90%.
D. Take a new sample from the population using the exact same sample size.
E. Take a new sample from the population using a smaller sample size.