Download Appendix 7.2 Confidence Intervals Using MegaStat

Appendix 7.2
Confidence Intervals Using MegaStat
Appendix 7.2 ■ Confidence Intervals Using MegaStat
Confidence interval for the population mean debt-toequity ratio:
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Select Add-Ins : MegaStat : Confidence Intervals /
Sample Size
•
In the “Confidence Intervals / Sample Size” dialog
box, click on the “Confidence Interval—mean” tab.
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Enter the sample mean (here equal to 1.3433) into
the Mean window.
•
Enter the sample standard deviation (here equal
to .1921) into the “Std Dev” window.
•
Enter the sample size (here equal to 15) into the
“n” window.
•
Select a level of confidence from the pull-down
menu or type a desired percentage.
•
Select a t-based or z-based interval by clicking on
“t” or “z.” Here we request a t-based interval.
•
Click OK in the “Confidence Intervals / Sample
Size” dialog box.
Confidence interval for a population proportion in
the cheese spread situation:
•
In the “Confidence Intervals / Sample Size”
dialog box, click on the “Confidence interval—p”
tab.
•
Enter the sample proportion (here equal to .063)
into the “p” window.
•
Enter the sample size (here equal to 1000) into
the “n” window.
•
Select a level of confidence from the pull-down
menu or type a desired percentage.
•
Click OK in the “Confidence Intervals / Sample
Size” dialog box.
Sample size determination for a proportion problem:
•
In the “Confidence Intervals / Sample Size” dialog box, click on the “Sample size—p” tab.
•
Enter the desired margin of error (here equal to
0.02) into the “E” window and enter an estimate
of the population proportion into the “p”
window.
•
Select a level of confidence from the pull-down
menu or type a desired percentage.
•
Click OK in the “Confidence Intervals / Sample
Size” dialog box.
Sample size determination for a population mean
problem is done by clicking on the “Sample Size—
mean” tab. Then enter a desired margin of error, an
estimate of the population standard deviation, and
the desired level of confidence. Click OK.
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