In a one-way between groups ANOVA, the dependent variable should be at which level?

In a one-way between groups ANOVA, the dependent variable should be at the interval or ratio level. This is because the analysis is designed to examine differences in means between groups, which requires that the dependent variable be measured on a scale that permits arithmetic operations, such as addition and subtraction.

Interval and ratio levels both provide a continuous scale of measurement that possesses meaningful intervals. In an interval scale, the difference between values is interpretable, although it does not have a true zero point (for example, temperature in Celsius). A ratio scale, on the other hand, includes a meaningful zero point, allowing for the comparison of absolute magnitudes (such as height or weight).

Using a dependent variable at the interval or ratio level ensures that the assumptions of ANOVA—such as normality and homogeneity of variance—are appropriately met, facilitating a valid interpretation of the results. Other levels of measurement, like nominal or ordinal, do not provide the necessary information for mean comparisons, making them unsuitable for this type of statistical analysis.