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## Class 8 (Foundation)

### Course: Class 8 (Foundation)>Unit 7

Lesson 2: Bar graphs

# Reading bar charts: comparing two sets of data

A bar chart is especially useful with comparing two sets of data. The difference in the bars give us a quick snapshot that allows us to draw some conclusions. Created by Sal Khan.

## Want to join the conversation?

• At Sal said 80 and 85. what is the answer?
• 85. He's not really saying 80, he's just hesitating a bit the first time and starts over saying 85. Looks like 80... like 85.
• when ever the blue line is not all the way on a number will it allways be 5?
• On the Khan Academy practice shown, yes, because they're counting by tens on the y-axis scale and the bars in between are always exactly half way in between.

In other situations, though, not always. You have to look carefully at the bar and the y-axis scale to see where the bar is and what they're counting by.
• What is the difference between "bar chart" and "bar graph"?
• they're the same thing, just different names :)
• Why do I get more energy points from watching a video than from answering 7 questions right?
• which website are u using for bar-chart in this video?
• I think you cut the numbers in hkf
• what if the bar is in between the line
• If the bar ends between two lines you just estimate where it ends. In the example on the video they all end halfway between the two numbers, making it 5 points more than lower of the two numbers.
(1 vote)
• At it says about 75 points. I tried to guess the amount of points in Reading bar charts 2 and I said I said it looked like 42 but it said I was wrong. How am I supposed to know the exact amount?
(1 vote)
• Jus guess
(1 vote)
• This seem like a practice video ,where can I learn statistics from the basic level to the most advance level on this website
(1 vote)
• why does there have to be 6 things why can't it just be less than 6
(1 vote)

## Video transcript

So we have this bar chart here. This says Scores on Midterm and Final Exams. So this axis, the vertical axis, is the scores. And then it's by student. And the blue bar is the midterm, and the yellow bar is the final. And the question they ask us is by how many points did Nadia's score improve from the mid-term to the final exam? So let's look at Nadia. So this is who we're talking about-- Nadia. And we care about how many points did she improve from the midterm to the final. Midterm is blue, final is yellow. So on the midterm, it looks like she scored-- and if I were to eyeball it, it looks like 75 points. And on the final, it looks like she scored 80. It looks like she scored 85 points. So it looks like her score improved by 10 points, so 10 points. Let's try one more. How many students improved their scores from the midterm to the final exam? So to improve from the midterm to the final, that means that the yellow bar for a given student, which is the final, is going to be higher than the midterm bar. That's the only way you can improve from the midterm to the final. So Brandon improved from the midterm to the final. Vanessa improved from the midterm to the final. Daniel improved from the midterm to the final. Kevin improved from the midterm to the final. William got a lower score on the final than the midterm, so he did not improve. So the number of students that improved their scores from midterm to final are one, two, three four students, so 4 students.