Correlation: Introduction to Relationships

In the last lesson, you learned about the Two-way Chi-square Test for Independence. Using it, you can determine if two categorical variables are independent. If two variables are not independent, they are related. Knowing something about one variable can tell you something about the other variable. In this lesson, you will explore further this idea […]

Correlation and Chi-square Tests for Independence

The word “correlate” has several meanings, e.g. “If two or more facts, numbers, etc. correlate or are correlated, there is a relationship between them” (Cambridge Dictionary, n.d.) And “to show that a close connection exists between (two or more things)” (Merriam-Webster, 2019)  Also, “to show that two things are connected.” (Macmillan, n.d.) In statistics, we often […]

Plotting lines given points and equations

If you need to find the equation of a line or its plot and you are given just two points, e.g. (5,5)(9,9), the best way to get the right answer is to use the WolframAlpha calculator at this page:,5)+and+(9,9) If you are given the equation of a line and you need to plot it, […]


This headline popped up in my newsfeed this morning: Boys will be boys: Data error prompts U-turn on study of sex differences in school (Retraction Watch, 2017) The article is about a peer-reviewed article on self-regulation of study habits that was published earlier this year. In the retraction, the authors noted they had discovered a […]

What to do about outliers?

The most recent assignment in my BUS 430 class was on simple linear regression. In some of the data sets, there are data points that seem to be inconsistent with the bulk of the data. One student called this to my attention and asked if he should just ignore those data points because they were […]