10-18 math

# The formulas for effect size for all three ttests are

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Unformatted text preview: words, there’s a 5% chance we’ll get data that lead to a confidence interval that doesn’t contain the true value. That means there’s a 95% chance we’ll end up with a confidence interval that does contain the true value. This is why it’s called a 95% confidence interval. You can also get confidence intervals for any other level of confidence, by changing α. As the example of 95% confidence shows, the confidence level is always 1 minus the alpha level. confidence = 1 – α (10) Keep in mind that the alpha level affects the confidence interval by determining tcrit. A smaller value of α (i.e., more confidence) leads to a larger tcrit (see Eq. 7), which leads to a wider confidence interval. Formulas for Cohen's d. Cohen’s d measures effect size relative to the standard deviation of the raw scores....
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## This document was uploaded on 02/25/2014 for the course PSYC 3101 at Colorado.

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