The Difference between Two Means
Computations for Unequal Sample Sizes (optional)
Answers
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The distributions are skewed and therefore violate the assumption of normality.
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Population 1 is skewed and therefore violates the assumption of normality. Population 2 has a larger variance.
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Population 2 has a larger variance.
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The statistic is the value you are interested in testing. Here you are interested in the difference between means.
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The hypothesized value is the population parameter you are comparing your statistic to. Here you are interested in the difference between population means.
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If the population means are equal, then the hypothesized value of the difference between means is 0.
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Since the statistic in question is the difference between means, the denominator is the estimated standard error of the difference between means.
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Compute the
for an independent-groups
test. If you are using a program, make sure to recode the data as described. 



