In Minitab 13, the test for equal variance is commonly referred to as Levene's Test. This test assesses whether multiple groups have the same variance, which is an important assumption for various statistical analyses. It is particularly useful when comparing variances across samples that may not follow a normal distribution. The results help determine if the assumption of homogeneity of variances holds for subsequent analyses.
You run a post-hoc test after conducting an analysis of variance (ANOVA) and finding a significant result. A post-hoc test is used to determine which specific groups differ significantly from each other, as ANOVA only tells you that there is a difference somewhere but not which groups are different.
Analysis of Variance (ANOVA) compares 3 or more means. The t-test would only compare 2 means.
same as one way anova population variance equal among groups noramlly distributed independent samples
Yes.For some tests, such as the Fisher F-test, the test statistic is an estimate of the variance. If the alpha level was not affected, the test would be no use at all!Yes.For some tests, such as the Fisher F-test, the test statistic is an estimate of the variance. If the alpha level was not affected, the test would be no use at all!Yes.For some tests, such as the Fisher F-test, the test statistic is an estimate of the variance. If the alpha level was not affected, the test would be no use at all!Yes.For some tests, such as the Fisher F-test, the test statistic is an estimate of the variance. If the alpha level was not affected, the test would be no use at all!
The t-test value is calculated using the sample mean, the population mean, and the sample standard deviation (which is derived from the sample variance). Specifically, the formula for the t-test statistic incorporates the sample variance in the denominator, adjusting for sample size through the standard error. A smaller sample variance typically results in a larger t-test value, indicating a greater difference between the sample mean and the population mean relative to the variability in the sample data. Thus, the relationship is that the t-test value reflects how the sample variance influences the significance of the observed differences.
Equal Variance
Equal Variance
The error in which a particular numbers are set apart is called error variance.
Analysis of Variance (ANOVA) compares 3 or more means. The t-test would only compare 2 means.
You run a post-hoc test after conducting an analysis of variance (ANOVA) and finding a significant result. A post-hoc test is used to determine which specific groups differ significantly from each other, as ANOVA only tells you that there is a difference somewhere but not which groups are different.
The Fisher F-test for Analysis of Variance (ANOVA).
same as one way anova population variance equal among groups noramlly distributed independent samples
Yes.For some tests, such as the Fisher F-test, the test statistic is an estimate of the variance. If the alpha level was not affected, the test would be no use at all!Yes.For some tests, such as the Fisher F-test, the test statistic is an estimate of the variance. If the alpha level was not affected, the test would be no use at all!Yes.For some tests, such as the Fisher F-test, the test statistic is an estimate of the variance. If the alpha level was not affected, the test would be no use at all!Yes.For some tests, such as the Fisher F-test, the test statistic is an estimate of the variance. If the alpha level was not affected, the test would be no use at all!
The t-test value is calculated using the sample mean, the population mean, and the sample standard deviation (which is derived from the sample variance). Specifically, the formula for the t-test statistic incorporates the sample variance in the denominator, adjusting for sample size through the standard error. A smaller sample variance typically results in a larger t-test value, indicating a greater difference between the sample mean and the population mean relative to the variability in the sample data. Thus, the relationship is that the t-test value reflects how the sample variance influences the significance of the observed differences.
The F-test (when used in an Analysis of Variance Problem): F = Mean square between / Mean square within If F=1, Mean square within and Mean square between are almost equal.
One way to test for heteroskedasticity in a statistical analysis is to use the Breusch-Pagan test or the White test. These tests examine the relationship between the error terms and the independent variables in a regression model to determine if the variance of the errors is constant. If the test results show that the variance is not constant, it indicates the presence of heteroskedasticity.
Variance is basically the raw material of statistics. If you don't have variance (differences in scores) you don't have much to work with or for that matter you don't have much to talk or think about. Consider a test where everyone gets the same score. What does that tell you? You might have some measurement problem, wherein the test is so easy everyone aces it. Still it might be so hard that everyone gets a zero. Now consider two tests. On each everyone gets the same score. That is on test one everyone gets a 15 and on the second test everyone gets a 10. That isn't telling you much is it? Now these are extreme cases, but in general, more variance is better and less variance isn't so good.