here are some data ... say we randomly assigned 30 Ss ... 15 to each
condition and found the following:
MTB > desc c1 c2
Descriptive Statistics: exp, cont
Variable N Mean Median TrMean StDev SE Mean
exp 15 26.13 27.00 26.00 4.96 1.28
cont 15 21.73 22.00 21.85 3.95 1.02
MTB > twos c1 c2
Two-sample T for exp vs cont
N Mean StDev SE Mean
exp 15 26.13 4.96 1.3
cont 15 21.73 3.95 1.0
Difference = mu exp - mu cont
Estimate for difference: 4.40
95% CI for difference: (1.04, 7.76)
T-Test of difference = 0 (vs not =): T-Value = 2.69 P-Value = 0.012 <<<<<
p value
MTB > let k1=(26.13-21.73)/3.95
MTB > prin k1
Data Display
K1 1.11392 <<<< simple effect size calculation
other than being able to say that the experimental group ... ON AVERAGE ...
had a mean that was about 1.11 times (control group sd units) larger than
the control group mean, which is purely DESCRIPTIVE ... what can you say
that is important?
_________________________________________________________
dennis roberts, educational psychology, penn state university
208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED]
http://roberts.ed.psu.edu/users/droberts/drober~1.htm
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