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Published byAmberly Porter Modified over 9 years ago
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t Test Assumptions: Paired/dependent/matched Samples:
two matched or paired samples data from populations are assumed to approximate a normal distribution Variance for both samples are approximately equal Observations must be independent of each other outliers Max value 75th percentile Median 25th percentile Min value
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One-tailed vs. Two-tailed test of significance.
With a two-tailed test of significance (at the .05 level), the alpha is split so that both directions can be covered. With a one-tailed test of significance the alpha is not split and is applied to one direction – with a one-tailed test you are testing for significance in one direction and disregarding the possibility of significance in the other direction. The one-tailed test is more likely (more powerful) in finding significance.
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Group A – McDonald’s Coffee
Within Group Variance Sampling Error Variance Mean
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Group B – Tim Horton’s Coffee
Within Group Variance Sampling Error Variance Mean
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Group A – McDonald’s Coffee
Group B – Tim Horton’s Coffee Mean Mean
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Group B – Tim Horton’s Coffee
Group A – McDonald’s Coffee Mean Mean Between Group Variance
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