Lesson video

Hello, my name is Mr. Clasper and today we are going to be using a line of best fit on a scatter graph.

A student revises for one hour.

What would their math test score be? Well to do this, I would need to draw something which is called a line of best fit.

A line of best fit represents the overall trend of the data.

It needs to be as close to as many of the points as we can.

And we normally ignore outliers.

This is our line of best fit.

If a student revises for one hour, we could use the line of best fit to find an approximation for their test score.

So if we read from the time axes at one hour and read across from our line of best fit, we would find that a student should get a score of around 26.

Let's take a look at a different example.

Using the same graph and line of best fit, a student has a test score of 38.

How long did they revise for.

Well, this time we need to find 38 on the score of maths test axes or the Y axis and read across to our line of best fit.

Then we can read down.

And this means that a student achieving a score of 38 would have spent three hours revising.

Again, this is an estimate based on our line of best fit.

Here is a question for you to try.

Pause the video to complete your task and click resume once you're finished.

And here are your solutions.

So if we look at the graph, we've got a line of best fit.

Obviously your line of best fit may be slightly different, and this may impact your answer for part B.

So using this line of best fit, we've got an approximate age of seven years.

However, if you've got an amount which is close to seven, this would suggest that you've still done the right thing.

And here is question two.

Pause the video to complete your task.

Click resume once you're finished.

And here are your solutions.

So for part A, remember your line of best fit must be as close to as many of the points as possible, following the trend of the data.

And we ignore outliers.

So you can ignore the point at the top left of the graph.

And for part B, we can't find the number of accidents for an eight year old as this is outside the range of the data which has been displayed on the graph currently.

And that's the end of our lesson.

So you can use a line of best fit on a scatter graph.

Why not try out the exit quiz just to show off your skills further.

I'll hopefully see you soon.