Definition
Bivariate data
Bivariate data pairs two variable values for the same person, object, or case.
Continue from this idea into connected AXIO math.
Two values travel as a pair, like a zipped row.
Boundary: Two separate lists are not useful as bivariate data unless each value in one list is paired with the matching case in the other.
What it means
Picture two columns joined row by row. Each row belongs to one case, so its two values must stay together. Looking across the pairs can show whether changes in one variable tend to go with changes in the other.
Remember it
Two values travel as a pair, like a zipped row.
Example
For three seedlings, record height and leaf count together: (10 cm, 4), (14 cm, 6), and (18 cm, 7). These three paired observations are bivariate data that can be checked for an association.
Watch for
Two separate lists are not useful as bivariate data unless each value in one list is paired with the matching case in the other.
Common mix-up
One ordered pair is one observation; bivariate data is the collection of paired observations.
Exact meaning
Bivariate data records two variable values for each case, keeping the two values paired so their relationship can be studied.