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Chapter 13: Confidence Intervals – Small Samples
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Also the distribution for the following statistics will have a
t
-distribution
with degrees of freedom
– 2.
These properties and conditions can aid us in the construction of a
(1 -
)
100% confidence interval for the difference between two
independent population means for small independent samples.
The general equation used in constructing a (1 -
)
100% confidence
interval for the difference between two population means for small
independent samples is given next.
Note:
The degrees of freedom which will be used in the equation is
–
2
.
Example 13-5:
A student wanted to determine whether there was a
difference between the miles per gallon for foreign and domestic compact
cars. A sample of 12 domestic cars was selected, and a sample of 13 foreign