Linear regression is best suited for which type of dependent variable?

Linear regression is best suited for dependent variables measured on a ratio scale that are also normally distributed. This is primarily because linear regression assumes that the relationship between the independent and dependent variables is linear, which is most accurately represented when the dependent variable has these characteristics.

A ratio scale provides meaningful distances between values and has an absolute zero point, allowing for robust statistical analyses including means and variances, which are foundational in linear regression. Additionally, the assumption of normality in the distribution of the dependent variable ensures that the results of the regression analysis, including hypothesis tests and confidence intervals, are valid. This combination allows for effective modeling of the relationship between variables and accurate predictions.

In contrast, count variables, which are discrete and do not have the same interval properties as ratio scales, may violate the assumptions of linear regression. Similarly, dichotomous variables, which have only two categories, would necessitate binary logistic regression as linear regression could lead to predictions outside the 0-1 range, making them impractical. Polytomous variables, representing more than two categories, would also not be suitable for linear regression due to the same reasons as dichotomous variables; different modeling techniques like multinomial regression are more appropriate for these types of data.