CONFIDENCE INTERVAL FOR THE DIFFERENCE OF MEANS ASSUMING EQUAL VARIANCE APPLET
INSTRUCTIONS
Once the applet has finished loading, a "Compute CI" and
a "Graphical CI" button will appear on the screen. This may
take a minute or two depending on the speed of your internet
connection and computer. Please be patient. If no begin
button appears, it is probably because your browser does
not support Java 1.1.
Starting the Applet and setting the conditions
1) Press the "Compute CI" button to start the applet in another window.
This applet is an easy-to-use Confidence Interval
Calculator. Once the user inputs the sample means, sample
standard deviations, sample sizes,
and selects the confidence interval to be
calculated(95% or 99%), clicking on the Execute button will
compute the large sample CI for the difference of the means
assuming equal variance for the two populations.
2) Press the "Graphical CI" button to start the graphical version of applet in another window.
This applet simulates sampling from a population with true
difference of the means of zero. For each sample, the 95% and 99%
confidence interval on the difference of the means is computed based on the
sample means, sample standard deviations, and sample sizes. The intervals for
the various samples are displayed by horizontal lines. If
the 95% or 99% confidence interval does not contain the
population difference (zero), it is shown in red.
If it contains the population difference, it is shown in green.
The CI limits for a sample size between 5 and 30 can be
obtained on the graph by moving the slider bar. Also specify
whether 95% or 99% confidence interval is needed by
selecting the appropriate checkbox. For example, selecting a
sample sizes of 5 and 95% CI would imply that 100 samples of
sample sizes 5 would be taken from the large
populations and the resulting 100
confidence intervals will be plotted.
The cumulative number of confidence intervals containing and not
containing the population difference of the means is tallied.