Select the FALSE statement related to ANOVA. A) The alternative hypothesis is at least one population mean is different from the others. B) It is used to test the equality of three or more population means. C) The ANOVA test can be a two-tailed test. D) It requires the populations to have the same variance
Select the FALSE statement related to ANOVA.
A) The alternative hypothesis is at least one population mean is different from the others.
B) It is used to test the equality of three or more population means.
C) The ANOVA test can be a two-tailed test.
D) It requires the populations to have the same variance.
The Correct Answer and Explanation is :
The FALSE statement is:
C) The ANOVA test can be a two-tailed test.
Explanation:
What is ANOVA?
Analysis of Variance (ANOVA) is a statistical method used to determine whether there are significant differences between the means of three or more groups. It is widely used in experimental designs and compares the variability between group means with the variability within the groups.
Evaluation of Each Statement:
- A) The alternative hypothesis is at least one population mean is different from the others.
- True. The null hypothesis in ANOVA is that all population means are equal. The alternative hypothesis is that at least one mean is different, which ANOVA tests for using the F-statistic.
- B) It is used to test the equality of three or more population means.
- True. ANOVA is specifically designed for testing differences in means across three or more groups. For two groups, a t-test is typically used.
- C) The ANOVA test can be a two-tailed test.
- False. ANOVA does not test specific directions (e.g., whether one mean is greater or smaller). Instead, it assesses whether there is a significant difference among group means. It is considered an omnibus test, which evaluates the overall variance across groups rather than the direction of differences.
- D) It requires the populations to have the same variance.
- True. ANOVA assumes homogeneity of variances, meaning that the variances across the groups should be equal. This is tested using methods like Levene’s test or Bartlett’s test.
Key Point:
ANOVA is not directional (i.e., not two-tailed) because it evaluates differences among multiple groups as a whole rather than specifying whether one mean is higher or lower. If further insight into specific group differences is needed, post-hoc tests like Tukey’s test are used.