Which type of test is commonly used to check equality of variances in multiple groups?

Levene's test is primarily utilized to assess the equality of variances across multiple groups. This statistical test is important because many parametric analyses, such as ANOVA, assume that the variances of the different groups being compared are equal. If this assumption is violated, it can lead to inaccurate conclusions regarding the differences among groups.

Levene's test does this by evaluating whether the absolute deviations of each group's scores from their respective group means are equal across all groups. A significant result from Levene's test indicates that the variances are not equal, which may require the use of alternative statistical methods or adjustments to the analysis.

In contrast to other tests listed, Bartlett's test, while also used to check for equality of variances, is sensitive to departures from normality. Therefore, it is typically used under the assumption that the data follows a normal distribution, limiting its applicability in real-world situations where that assumption may not hold. Mixed factorial ANOVA, on the other hand, is an analytical technique rather than a test for variance, and the chi-square test is utilized for categorical data analysis, not for checking variances. Hence, Levene's test stands out as the most appropriate choice for this specific purpose.