Click the Cite button above to demo the feature #to enable visitors to import publication metadata #into their reference management software ..read more

Click the Cite button above to demo the feature #to enable visitors to import publication metadata #into their reference management software ..read more

Click the Cite button above to demo the feature #to enable visitors to import publication metadata #into their reference management software ..read more

Click the Cite button above to demo the feature #to enable visitors to import publication metadata #into their reference management software ..read more

Click the Cite button above to demo the feature #to enable visitors to import publication metadata #into their reference management software ..read more

Chi-square Chi-square is typically used to test the relationship between two categorical variables. For example, does a car have an automatic transmission is a categorical variable. The age of an individual is a continous variable. Chi-square is for testing relationships between variables like the former. Thus our Null hypothesis (H0) would be: There is no significant relationship between two categorical variables. And our Alternative hypothesis (H1) would be: There is a significant relationship between two categorical variables. Typically your variables can be visualized in a bivariate table ..read more

What is an interaction? What’s first discuss what it is not. It has nothing to do with the dependent variable (Y). It never involves only one independent variable, it must involve two or more. An interaction can be defined as one independent variable changing the effect of another independent variable on the dependent variable. If you haven’t read my post on MANCOVAs, please do so before continuing so the code will make sense. This post will use the example problem from there. I’ll quickly rehash it. From MANCOVA post“our question is does chick weight from time point 2 to time point 4 differ d ..read more

What is an interaction? What’s first discuss what it is not. It has nothing to do with the dependent variable (Y). It never involves only one independent variable, it must involve two or more. An interaction can be defined as one independent variable changing the effect of another independent variable on the dependent variable. If you haven’t read my post on MANCOVAs, please do so before continuing so the code will make sense. This post will use the example problem from there. I’ll quickly rehash it. From MANCOVA post“our question is does chick weight from time point 2 to time point 4 differ d ..read more

MANCOVA If you’ve been following along my posts, you can probably guess what a MANCOVA is good for. Basically, take the concepts of MANOVA and ANCOVA and suh whoo, you got a MANCOVCA. In case you haven’t been following along, I’ll explain what a MANCOVA is good for. For this example, our question will be does chick weight from time point 2 to time point 4 differ depending on diet removing variance associated with weight when the chick was born. It’s simliar to the MANOVA in that it can model differences between three or more variables and it’s similar to an ANCOVA in that it can remove the var ..read more

What if you didn’t run the most perfect tightly controlled study and you’re worried there might be some covariate influencing your dataset. We can do that by running a quasi experiment using an Analysis of Covariance (ANCOVA) model. While it doesn’t perfectly control for the confound, it’s a useful tool to mitigate the noise it introduces into your data. In this example I’ll be using the dataset mtcars included in base R. data(mtcars) summary(mtcars) ## mpg cyl disp hp ## Min. :10.40 Min. :4.000 Min. : 71.1 Min. : 52.0 ## 1st Qu.:15.43 1st Qu.:4.000 1st Qu.:120.8 1st Qu.: 96.5 ## Median :19.2 ..read more