AS Biology - Line of best fit (Drawing graphs)

I did an experiment on the effect of substrate concentration on rate of reaction.
My experiment didn't produce very concordant results. There is no pattern anywhere...they're just random :s-smilie:

I'm plotting a graph with y-axis rate of reaction and x-axis concentration.

But I don't know how to draw the line of best fit? Is it a straight line to each point or straight line through the middle of all the points or is it curved?

Reply 1

Eloades11

17

Original post by ItsAnnaYay

I did an experiment on the effect of substrate concentration on rate of reaction.
My experiment didn't produce very concordant results. There is no pattern anywhere...they're just random :s-smilie:

I'm plotting a graph with y-axis rate of reaction and x-axis concentration.

But I don't know how to draw the line of best fit? Is it a straight line to each point or straight line through the middle of all the points or is it curved?

If wouldn't be a line of best fit if it were through all the points, so usually you'd draw a straight line connecting all the points as much as possible.

In this case, you want a curve as your graph should look something like this

Reply 2

ItsAnnaYay

OP

4

Original post by Eloades11

If wouldn't be a line of best fit if it were through all the points, so usually you'd draw a straight line connecting all the points as much as possible.

In this case, you want a curve as your graph should look something like this

So to draw the curve does it have to go through all points? (because I don't think my graph will look like that, because my results fluctuate, I'm worried it'll look like a zigzag)

Could you please explain to me what you mean by "you'd draw a straight line connecting all the points as much as possible."
Like dot to dot? or one straight line connecting points before the saturation point and another line after?

I fail at experiments.

(edited 12 years ago)

Reply 3

Eloades11

17

Original post by ItsAnnaYay

So to draw the curve does it have to go through all points? (because I don't think my graph will look like that, because my results fluctuate, I'm worried it'll look like a zigzag)

Could you please explain to me what you mean by "you'd draw a straight line connecting all the points as much as possible."
Like dot to dot? or one straight line connecting points before the saturation point and another line after?

I fail at experiments.

Nope, there's a difference between connecting all of the points by joining them up and drawing a line of best fit. A line of best fit is where you try and connect the points as much as possible with 1 straight line. Here's a quick example I've drawn on paint.

I've also attached a quick line of best fit which is curved. As you can see, the lines cannot go through all the points but it's close.