The histogram below shows the test results as a percentage from a group of students' mathematics exam.
Histogram representing test results, Thomas-Gay - StudySmarter Originals
Here are a set of questions that you can answer from the histogram above:
How many students scored between 75% and 85% on the exam?
How many students scored between 60% and 70% on the exam?
How many students scored 80% or more on the exam?
How many students took the exam in total?
Now let's work through each question together!
How many students scored between 75% and 85% on the exam?
First, you start by looking at the histogram. You need to find the area of the bars between 75 and 85, and they are shaded below:
Histogram worked example, Thomas-Gay - StudySmarter Originals
To find the shaded area we can simply multiply the height by the width:
Therefore we know that 10 students scored between 75% and 85%.
2. How many students scored between 60% and 70% on the exam?
This can be done in the same way, let's start by shading the area needed on the graph:
Histogram worked example, Thomas-Gay - StudySmarter Originals
For this area, you will need to break it down into two parts since you are looking at two different bars:
This shows you that around 20 students scored between 60% and 70% on the exam.
3. How many students scored 80% or more on the exam?
Once again let's start by shading the area that is needed, for this question you need to shade everything over 80%:
Histogram worked example, Thomas-Gay - StudySmarter Originals
This question again needs to be broken down into two parts:
This shows that 14 of the students scored 80% or more on the exam.
4. How many students took the exam in total?
For this question, you need to find the area of each bar, your shaded area will now look like this:
Histogram worked example, Thomas-Gay - StudySmarter Originals
You will need to find the area for each bar and add them all together to find the total number of students:
Now you can add them all together to find the total number of students.