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Chapter 13: Confidence Intervals – Small Samples
we will use the
Critical
-values
workbook to find
-values for typical
values.
Example 13-1:
What is the value of
?
Solution:
Using the workbook, enter the value of 10 as the degrees of
freedom. Note that 5%
0.05. So from the workbook,
= 1.8125 to
four decimal places.
Figure 13-3
shows the resulting display from the
Critical
t
-values
workbook.
Figure 13-3:
Display with
Example 13-2:
What is the value of
?
Solution:
We can use the symmetric property of the
-distribution to find
. Since 0.95 area is to the right of this
-value then the value must be
negative. Also, since 0.05 area is to the left of this
-value, then
-
= - 1.8125. We can also use the
-distribution workbook to obtain
the answer.
Figure 13-4
shows the result.
Figure 13-4:
Display with