MedVision ad

curve of best fit (1 Viewer)

crammy90

Member
Joined
Mar 26, 2006
Messages
264
Gender
Male
HSC
2008
when do we use this instead of a line of best fit?
 

frogbutt

Ugliest Member
Joined
Jan 4, 2008
Messages
61
Gender
Female
HSC
2008
when the points make an obvious curve shape...or think about the trend it's showing and see if you KNOW that it's not supposed to be linear.

in hsc its usually pretty obvious. they just have some outliers you're supposed to ignore.
 

JasonNg1025

Member
Joined
Oct 14, 2007
Messages
295
Gender
Male
HSC
2010
I haven't seen many situations where you have to plot a curve of best fit.

Use what frogbutt said, however, be careful when something <i>looks</i> like a curve, if it goes sorta similar to a line (curving up very slightly). If the last value is higher, making the line look like a curve, it probably isn't - sometimes they test to see if you can find experimental errors and learn to negate them.
 

crammy90

Member
Joined
Mar 26, 2006
Messages
264
Gender
Male
HSC
2008
now im confused lol
should i just use a line of best fit for everything? ive never been taught curve of best fit...
absorption would be line of best fit yeh?
 

Trebla

Administrator
Administrator
Joined
Feb 16, 2005
Messages
8,391
Gender
Male
HSC
2006
Within the context of the HSC course, I think you're only expected to know how to do a line of best fit, except perhaps for a titration curve?

You should be able to tell theoretically whether some relationship is linear or not. For example, you should know that plotting a calibration curve for AAS shows a linear relationship between absoprtion (A) and concentration (c) (the theoretical equation is given by A = εcl where ε and l are kept as constants, I think it's called the Beer-Lambert law). On the other hand, you should know the shape of a titration curve and why the curve is of that nature. So if you were asked to plot pH changes over time, then you would expect to use a curve of best fit (though it's highly unlikely you will be asked to do that).
 

JasonNg1025

Member
Joined
Oct 14, 2007
Messages
295
Gender
Male
HSC
2010
By some law outside of our syllabus, AAS should technically produce a straight line. Unfortunately, the HSC is not that kind to you...
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top