To determine the effect size measure for the t-text the Cohen's d. Cohen's d is the appropriate effect size measure for t-test if two groups have the same standard deviations. Cohen's d is calculated by determine the mean difference between two groups and then dividing the results according their pool standard deviation.
Question 1 The effect size measure for a t-test is Eta Squared Correlation value Cohen’s D Correct! Correct! Crammer’s V. 8/18/2018 Week 5 - Quiz: BUS308: Statistics for Managers (BAM1823B) 1 / 1 pts Question 2 Confidence intervals provide an indication of how much variation exists in the data set. True Correct! Correct!
For the t-test, the effect size measure is Cohen’s d = (difference between the means)/(standard deviation of the entire sample.) Note that the standard deviation of the entire sample (both groups combined) is not provided within the t-test output, you will need to have access to the samples tested to generate this value.
Jun 29, 2018 · The effect size measure for a t-test is Cohen’s D Cohen ’s D An Effect size measure should be calculated when we fail to reject the null hypothesis, as it explains what influenced this decision was made.
T-test conventional effect sizes, poposed by Cohen, are: 0.2 (small efect), 0.5 (moderate effect) and 0.8 (large effect) (Cohen 1998, Navarro (2015)). This means that if two groups’ means don’t differ by 0.2 standard deviations or more, the difference is trivial, even if it is statistically significant.
The Welch test is a variant of t-test used when the equality of variance can’t be assumed. The effect size can be computed by dividing the mean difference between the groups by the “averaged” standard deviation.