Using the formula for the margin of error, it is found that a smaller confidence interval would be obtained as follow:
D. Increase the sample size to 64.
What is the margin of error of a confidence interval?
It is given by the following formula:
[tex]M = z\frac{s}{\sqrt{n}}[/tex]
In which:
- z is the critical value(direct proportional with the confidence level).
- s is the standard deviation.
For a smaller interval, we need to decrease the margin of error, which is possible increasing the sample size, hence option D is correct.
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