Discussion of the Example
Before even answering the specific questions, we first take
a look at the graph to get an idea of what information it contains.
We see that this is a graph of enrollment figures in five introductory
courses at Union University.
As we look more closely, we notice the data groups are not
ordered, but are nominal level categories, class name. The frequency
data is given in numbers of students enrolled in a course. The
scale does begin at zero, and goes to 350. This allows us to make
comparisons between bar heights.
Now let's look at the specific questions.
- Which course has the most students
enrolled in it?
Introductory Econ has the most students enrolled.
Since the height of each bar is a measure of the number of students
enrolled, we simply need to look for the tallest bar.
- Order the courses by enrollment from
lowest to highest.
From lowest to highest: Physics, Chem, Psych, Poly Sci, Econ.
As with the previous question, we can answer this question by
simply looking at the height of the bars, and ordering them from
shortest to tallest.
Enrollment in Introductory
- The enrollment in Econ is approximately
how many times bigger than the enrollment in Chem?
The first thing you should realize is that the answer to this
question is the ratio of the number of students enrolled in Econ
to the number enrolled in Chem. This ratio is also the ratio
of the heights of the two bars:
- Approximately, how many students were
enrolled in the course with the most students?
There are approximately 340 students enrolled in the course
with the most students, which is Econ.
Estimating numbers off a bar graph is only an approximation.
Given the scale of the graph we cannot determine the exact number
enrolled. If we look at how tall the Econ bar is, we estimate
that 340 students are enrolled.
- Approximately how many more students
are in Econ than in Physics?
There are approximately 200 more students in Econ than in Physics.
For this question we want to have a number for the course
enrollment for Econ and Physics, then find their difference using
subtraction. As in the previous problem, we use bar heights to