HP 49g+ User Manual page 165

4. Z-INT: p p .: Confidence interval for the difference of two proportions,
p -p , for large samples with unknown population variances.
1 2
5. T-INT: 1 .: Single sample confidence interval for the population mean,
, for small samples with unknown population variance.
6. T-INT: .: Confidence interval for the difference of the population
means, - , for small samples with unknown population variances.
1 2
Example 1 – Determine the centered confidence interval for the mean of a
population if a sample of 60 elements indicate that the mean value of the
sample is x = 23.2, and its standard deviation is s = 5.2. Use
The confidence level is C = 1- = 0.95.
Select case 1 from the menu shown above by pressing
required in the input form as shown:
Press to obtain a screen explaining the meaning of the confidence
@ H E L P
interval in terms of random numbers generated by a calculator. To scroll
down the resulting screen use the down-arrow key
done with the help screen. This will return you to the screen shown above.
To calculate the confidence interval, press
calculator is:
Press to see a graphical display of the confidence interval information:
@ G R A P H
. Enter the values
@ @ @ O K @ @ @
˜
. Press
@ @ @ O K @ @ @
. The result shown in the
@ @ @ O K @ @ @
= 0.05.
when
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