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Chapter 11: Confidence Intervals – Large Samples
We can use the
Large Sample Confidence Interval for a Single Population
Mean
workbook to help with the computations.
Figure 11- 10
shows the
output with the 95% confidence interval. Observe the workbook assumes
normality since the results are reliable for any sample size.
Figure 11- 10:
Workbook Output with the Confidence Interval
Note:
When computing the confidence interval for a single population mean,
if the population standard deviation
is unknown, we can replace it with the
sample standard deviation
s
if the sample size is large enough. That is, if
n
30.
The equivalent equation used in constructing the (1 -
)
100% confidence
interval for the population mean when
is unknown and
30 is given by
Click here for the Large Sample Confidence Interval for a Single Population Mean Workbook