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i don't really get histograms,if they give you half the graph but no frequecy density , WHAT DO YOU DO?--help PLEASE......

and what are formulas for median and and lower quartile range?


Posted Sat 9th June, 2012 @ 23:29 by anonymous
Edited by anonymous on Sat 9th June, 2012 @ 23:30

8 Answers

  • 1 vote


You would have to work out the frequency density from the table using frequency density= frequency/class width. I remember this formula as Frankie Frog does Cartwheels! Click on my name for a video of a worked example!

Medians and Quartiles:

Order all the data you have (only if it is ungrouped)

N is the number of data

Position of the Median in list is (n+1)/2...because the M is the 1/2 way point. 

Position of the Lower Quartile is (n+1)/4...because the LQ is 1/2 of the median so 1/4.

Position of the Upper Quartile is 3(n+1)/4....because UQ is the M+LQ so 3/4.

The interquartile range is just the value of UQ (not position) - value of the LQ

(When you work out the normal range you minus the lowest number from the highest number and so it is the same concept)

If you don't really get this , look at the video I have uploaded (but it does explain it a little differently).

Hope this helps!! :)

Answered Sun 10th June, 2012 @ 08:22 by Dilly
Edited by Dilly on Sun 10th June, 2012 @ 08:23
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btw shouldn't your formulas be FRANKIE DOES FROG CARTWHEELS?:)

Answered Sun 10th June, 2012 @ 10:40 by anonymous
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No I do it from the frequency= frequency density * class width and put it in a triangle.

Sorry about the confusion!

Answered Sun 10th June, 2012 @ 10:49 by Dilly
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wat is the triangle for itt  ^^

Answered Sun 10th June, 2012 @ 11:13 by в
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The triangle is:



fd   cw

Answered Sun 10th June, 2012 @ 11:14 by Dilly
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Thank yuee i revise better with triangles!

Answered Sun 10th June, 2012 @ 11:14 by в
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ohh....thanks,yes i watched the video on your profile,and it the guy sort of rearranged the equation

Answered Sun 10th June, 2012 @ 11:25 by anonymous
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yhh dat video was gwd :)

Answered Sun 10th June, 2012 @ 11:35 by в