Line of best fit. (1 Viewer)

[nml10]

Could the line of best fit be a curve? I thought it was ALWAYS a straight line.
:S

 

[slyhunter]

yes

 

[romesh]

Well if it was a curve, it wouldn't be a 'line' of best fit! A line of best fit is necessarily going to be a straight line...'curve fitting' is the more general case, of which line fitting is a subset. You can fit any function you like to data, but to get a line of best fit you choose the function to have the form y=mx+b

 

[Aquawhite]

I think, for the HSC requirements, it is best to always provide a line of best fit which is linear. If you wish to (as I did) you can provide a line of best fit 'area' in which you specify the two extremes in which the 'best fit' could actually lie.

If it weren't HSC, it could be curved.

 

[s2 SEductive]

It needs to be a straight line, so u can find the gradient of it. If u draw a curve, u would need to find the tangent to a point, time wasting.

 

[Drongoski]

It needs to be a straight line, so u can find the gradient of it. If u draw a curve, u would need to find the tangent to a point, time wasting.

Blind leading the blind.

In HSC line of best fit occurs only in General Maths. It is based on method of least squares. In Gen Maths however ypu just try to fit a straight line thru set of points so that line is closest to the point. But this is so unreliable. The line fitted by 10 students will all be different and some very different. The correct method is beyond Gen Maths.

Also the line fitted need not be a straight line although usually is.

 

[jamesfirst]

My chemistry teacher told me that line of best fit can be a curve and it's good to draw a curve in a given situation. Especially for equilibrium graphs.


As far as I know, it's also for Physics.

 

[danjw]

Blind leading the blind.

In HSC line of best fit occurs only in General Maths.

LOL I have personally seen the line of best fit be involved in a HSC physics exam paper.

 

[Studentleader]

I have done physics experiments during highschool where a parabolic like line was required

 

[annabackwards]

In the HSC, the line of best fit is almost always a straight line.

The data plotted on the axis is usually manipulated so that is the case. For example, in the pendulum practical, T^2 plotted on the graph, not T (period). It is the same in uni, the data is manipulated so that the line of best fit is a straight line so values can be easily obtained.

However, a line of best fit can be a curve and if a curve fits the data better, draw a curve.

 

[s2 SEductive]

LOl then my teachers are misleading?

 

[slyhunter]

perhaps

 

[jamesfirst]

I thought it was a straight line too. But some graphs require a curved line of best fit.


I made this mistake and lost a mark in one of my practical assessments for chemistry.

 

[Aquawhite]

You aren't even going to have to draw a line of best fit in the exam anyway.

 

[danjw]

You aren't even going to have to draw a line of best fit in the exam anyway.

2006 HSC Question 20 Page 21
http://www.boardofstudies.nsw.edu.au/hsc_exams/hsc2006exams/pdf_doc/physics_06.pdf

Also appears in 2007 exam.