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Question 709
Statistics → Epidemiology
Classification
Question
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95% confidence interval
Question Stem
In a population of more than 30 observations, which expression is used to estimate the 95% confidence interval around a mean?
Options
A
Mean ± 0.95 SEM
B
Mean ± 1.00 SEM
C
Mean ± 1.64 SEM
D
Mean ± 1.96 SEM
E
Mean ± 2.58 SEM
Explanation
For a population of more than 30 observations, the 95% confidence interval around the mean is estimated as the mean plus or minus 1.96 standard errors of the mean.
Option Validity
A) 0.95 is not the multiplier used for a 95% confidence interval.
B) one SEM does not define the 95% confidence interval.
C) 1.64 SEM is not the stated multiplier for the 95% interval.
E) 2.58 SEM is not the stated multiplier for the 95% interval.
Further Reading
Review confidence intervals and the relationship between the mean and standard error of the mean.