Communication Research
Asking
Questions, Finding Answers
Joann Keyton, Ph.D.
Chapter 11
Testing
for Differences
Assessing
Differences Between Groups
This interactive web site provides a graphic view of the t-test. The mean of the distribution shown in blue is fixed at 50; but you can vary the distribution of other group shown in red. Try several different means for the red distribution. Notice how changing the mean changes the variance explained by the grouping, or nominal variable, which would be the independent variable. To help you understand the importance of the relative difference between the two distributions, imagine that the blue distribution represents females’ scores of communication apprehension and that the red distribution represents males’ scores of communication apprehension.
Ready to Review?
These websites, from
Have Data and Ready to
Compute a t-Test?
This GraphPad web site will let you enter your data for an independent sample t-test and compute your t-value.
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