Before we start analyzing, we need to make one more distinction between different types of data. Then our data can take a seat on the couch and we'll start getting to the root of its daddy issues.
Single-variable or univariate data refers to data where we're only observing one aspect of something at a time. With single-variable data, we can put all our observations into a list of numbers.
Sample Problem
We take a group of people, measure their heights, and get this list of heights:
5'2'', 5'4'', 6'1'', 5'9'', 5'3''.
This is univariate data, since we're only observing one aspect (the height) of each person.
With two-variable, or bivariate data, we observe two aspects. We can put our observations into a table. The columns-and-rows kind, not the upending-and-throwing-across-the-room-in-a-rage kind.
Sample Problem
We take a group of people, measure their heights and weights, and get the following information:
This is bivariate data, since we have observations about two aspects (the height and weight) of each person.
Exercise 1
Determine whether the following statement refers to univariate (single-variable) or bivariate (two-variable) data:
Jen measured the height and number of leaves of each plant in her laboratory.
Exercise 2
Determine whether the following statement refers to univariate (single-variable) or bivariate (two-variable) data:
Linda recorded the weight of each of her cats.
Exercise 3
Determine whether the following statement refers to univariate (single-variable) or bivariate (two-variable) data:
Roberto observed the color and model of each car in the parking lot.
Exercise 4
Determine whether the following statement refers to univariate (single-variable) or bivariate (two-variable) data:
Luigi found the shoe size of each of his customers.
Exercise 5
Determine whether the following statement refers to univariate (single-variable) or bivariate (two-variable) data:
Kenny wrote down the length of each song.