Line of best fit (1 Viewer)

[ProdigyInspired]

I'm still confused on how markers want us to do a line of best fit.

2015's Q22a) has dots all over the place. The MG shows its just a smoothed out connect the dots line.

Any ideas on how it should be generally done?

 

[InteGrand]

I'm still confused on how markers want us to do a line of best fit.

2015's Q22a) has dots all over the place. The MG shows its just a smoothed out connect the dots line.

Any ideas on how it should be generally done?

Here's the link to the 2015 HSC Chemistry Exam Marking Guidelines to save anyone the trouble of having to search it up, for those who want to see it: https://www.boardofstudies.nsw.edu.au/hsc_exams/2015/guides/2015-hsc-mg-chemistry.pdf (Question 22(a)'s guidelines are on page 3 of that document).

Here's the HSC Chemistry paper for that year: https://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-chemistry.pdf (Question 22(a) is on page 15).

I think since it said to draw a "line graph" (rather than "line of best fit"), the answers did what they did. Technically speaking, I think a "line graph" should be connecting adjacent data points by straight lines. E.g. see https://www.mathsisfun.com/definitions/line-graph.html , https://en.wikipedia.org/wiki/Line_chart , or other places online.

 

[ProdigyInspired]

Here's the link to the 2015 HSC Chemistry Exam Marking Guidelines to save anyone the trouble of having to search it up, for those who want to see it: https://www.boardofstudies.nsw.edu.au/hsc_exams/2015/guides/2015-hsc-mg-chemistry.pdf (Question 22(a)'s guidelines are on page 3 of that document).

Here's the HSC Chemistry paper for that year: https://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-chemistry.pdf (Question 22(a) is on page 15).

I think since it said to draw a "line graph" (rather than "line of best fit"), the answers did what they did. Technically speaking, I think a "line graph" should be connecting adjacent data points by straight lines. E.g. see https://www.mathsisfun.com/definitions/line-graph.html , https://en.wikipedia.org/wiki/Line_chart , or other places online.

its interesting since the marking guidelines specify "a line of best fit". Where as I'm not sure that's a line of best fit at all. I would've thought the line graph would just be adjacent connecting the dots too, but am always hearing about how that's frowned upon, and it has to be a line of best fit.

 

[ProdigyInspired]

Actually, if I recall correctly, I've gotten marked down for connecting the dots rather than a line of best fit in a line graph -.-

 

[InteGrand]

its interesting since the marking guidelines specify "a line of best fit". Where as I'm not sure that's a line of best fit at all. I would've thought the line graph would just be adjacent connecting the dots too, but am always hearing about how that's frowned upon, and it has to be a line of best fit.

The Marking Guidelines are dodgy. Plus, "line of best fit" is really supposed to refer to a straight line too (not sure whether HSC Science adheres to this though). What the Sample Answer did was some sort of curve of best fit. I guess just memorise what the sample answers do then (try searching for similar Q's in past papers and checking what some sample answers to them did).

 

[InteGrand]

Actually, if I recall correctly, I've gotten marked down for connecting the dots rather than a line of best fit in a line graph -.-

Probably for HSC Science purposes, it's safest to try doing a smooth curve of best fit.

 

[eyeseeyou]

Just curious but when do we use a line of best fit and when do we use a curve of best fit?

 

[KingOfActing]

Just curious but when do we use a line of best fit and when do we use a curve of best fit?

Line if the data is approximately linear
Curve if it's not

 

[ProdigyInspired]

Line if the data is approximately linear
Curve if it's not

in the past papers have you generally seen a curved line of best fit like 2015? haven't had time to do that many PP's.

 

[KingOfActing]

in the past papers have you generally seen a curved line of best fit like 2015? haven't had time to do that many PP's.

haven't done any, but curved is usually for exponential relationships (something to do with heat of combustion or something)