Data considerations for Covariance

To ensure that your results are valid, consider the following guidelines when you collect data, perform the analysis, and interpret your results.

The data should be continuous
If you have categorical data, you should perform Cross Tabulation and Chi-Square to examine the association between variables.
The relationship between the variables should be linear
If the variables have a nonlinear relationship, your results may be misleading. To check for nonlinear relationships graphically, use Scatterplot or Fitted Line Plot.