I've been curious ever since I first came across the term Cumulative Frequency 'Polygon' in maths class some 44 years ago. A polygon, by definition, is a shape bound by closed straight line segments. But since there is no closed shape whatsoever in 'Cumulative Frequency Polygon', where in the world is the 'polygon'?
Please, clarify if "class centre" was specific to this problem (not generally used, unless mentioned). Also, please explain why did we chose the formula to be as such?
We only use the class centre when the data has been organised into groups or classes. The class centre then becomes the centre of your columns for the histogram.
The class centre is the middle or centre of the class or group. You determine the centre of each class by adding the lower and upper limit of the class and then halve the result.
The score has to be centred in the column, so each column is one unit in width. It starts at 6.5 on the axis so the 7 is in the centre of the column. It does not mean there are scores of 6.5 or 6.7, etc. It is just for the convenience of having the scores in the centre of the column. That is important or you may get confused about what score goes with which column.
Thank you so much. It's literally minutes before my exam n I couldn't understand a thing. Its all so clear now
Glad I could help.
Awesome video! Learnt heaps, thank you very much!
Glad you found it helpful.
Thank you so much sir.
Glad I can help.
Thanks Ray, big help mate :)
Well understood, thank you
Thank you!.
thank you Ray !
No problem. Glad to help.
thx for the help
No worries. Glad to help.
Would it be more accurate to use "Upper Bounds" in the Class-Center axis after rounding all the classes? E.g. (14.5, 19.5, 24.5, 29.5, 34.5, 39.5)
For classes, the horizontal axis is to scale so there is an upper and lower bound.
Thank you sm
No worries. Glad to help.
I've been curious ever since I first came across the term Cumulative Frequency 'Polygon' in maths class some 44 years ago.
A polygon, by definition, is a shape bound by closed straight line segments.
But since there is no closed shape whatsoever in 'Cumulative Frequency Polygon', where in the world is the 'polygon'?
It does actually make a polygon. The horizontal axis forms part of the closed figure.
Please, clarify if "class centre" was specific to this problem (not generally used, unless mentioned). Also, please explain why did we chose the formula to be as such?
We only use the class centre when the data has been organised into groups or classes. The class centre then becomes the centre of your columns for the histogram.
So if I'm clear, the cumulative frequency histogram and cumulative frequency polygon are practically the same thing?
The histogram is the column graph. The polygon is the line graph. You do, however, draw the histogram to produce the points for the polygon.
@@raygrimson6961 Thank you so much!
What is class centre?
The class centre is the middle or centre of the class or group. You determine the centre of each class by adding the lower and upper limit of the class and then halve the result.
idk?
why did you start from 6.5 and not from 7?
The score has to be centred in the column, so each column is one unit in width. It starts at 6.5 on the axis so the 7 is in the centre of the column. It does not mean there are scores of 6.5 or 6.7, etc. It is just for the convenience of having the scores in the centre of the column. That is important or you may get confused about what score goes with which column.