HP 39gs Master Manual page 143

Confidence interval: T-Int 1-
In the previous example we found that the evidence of our sample indicated that the mean number of matches
in the boxes was not 50. Suppose we now want to know, at the 95% confidence level, within what range of
values the true population mean lies.
Change back to the
SYMB
Interval.
The type of interval is converted to the equivalent type of T-INT: 1
In the view use the import facility as before to import the
NUM SETUP
values from our sample data. The default confidence level is 99% so you
will need to change that to 0.95.
Changing to the view gives the minimum and maximum values for
NUM
the population mean of 50.16 to 52.44 at a 95% confidence level.
As before, a more visual display can be seen in the
Thus the sample data indicates in our two examples that:
we can be confident the average number of matches is not 50
•
with less than a 5% chance of being wrong, and
• we can conclude, with a confidence of 95%, that the true
average number of matches is between 50.16 and 52.44.
µ
view and the method of Conf
µ .
view.
PLOT
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