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Maths A Level Statistics - Histogram Help

How do you find the frequency in a histogram? I tried using the formula frequency density x class width = frequency but I heard something about a multiplier needed which is then multiplied by the area?

Please help!
Frequency is just area of the whole histogram
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badmathkid
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Original post by N/A IS THE NAME
Frequency is just area of the whole histogram


I know this but the answer was wrong apparently? A multiplier is needed. I'm not sure how the multiplier is worked out.
Original post by badmathkid
I know this but the answer was wrong apparently? A multiplier is needed. I'm not sure how the multiplier is worked out.


Are you talking about find the value of the yaxis
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badmathkid
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Original post by N/A IS THE NAME
Are you talking about find the value of the yaxis


The y axis is given as the frequency density and the x axis is given as mass.
Reply 5
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sarah5
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Original post by badmathkid
How do you find the frequency in a histogram? I tried using the formula frequency density x class width = frequency but I heard something about a multiplier needed which is then multiplied by the area?

Please help!


the area is proportional to the frequency
Reply 6
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badmathkid
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Original post by sarah5
the area is proportional to the frequency


I see, so how would I work it out in figures?
Original post by badmathkid
The y axis is given as the frequency density and the x axis is given as mass.


Then i dont think u need a multiplier- never heard of that.
Reply 8
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sarah5
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Original post by badmathkid
I see, so how would I work it out in figures?


send me the question so i can explain it
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badmathkid
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Original post by N/A IS THE NAME
Then i dont think u need a multiplier- never heard of that.


Someone explained to me that a multiplier is needed due to the proportionality and whenever I look at the answer it's not just simply the cw x fd.
Then there must a bit of info in the question that relates the mass on the y axis to the frequency they are looking for- or something like this.
Original post by sarah5
send me the question so i can explain it


I'm not exactly sur ehow I can attach an image of the question as it's a screenshot.
Original post by sarah5
send me the question so i can explain it


I've converted the images to URL links:


https://s1.postimg.org/8j7ddg3li7/My_Math_1.png
https://s1.postimg.org/4lezwrsskv/My_Math_2.png
Reply 13
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sarah5
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Original post by badmathkid


okay for the first question
area=k*frequency
then you need to find k
so you have
the mass from 1-4
and its width (4.5-0.5)=4
the frequency density =0.5
so width*fd=k*freqency (which is 10 given in the table )
4*0.5/10 =k (0.2)

then you need to find the frequency for 5-6 where the width (6.5-4.5)=2 and fd =4
the frequency = 2*4/0.2 =40
and so on ...
hope u understand
Original post by sarah5
okay for the first question
area=k*frequency
then you need to find k
so you have
the mass from 1-4
and its width (4.5-0.5)=4
the frequency density =0.5
so width*fd=k*freqency (which is 10 given in the table )
4*0.5/10 =k (0.2)

then you need to find the frequency for 5-6 where the width (6.5-4.5)=2 and fd =4
the frequency = 2*4/0.2 =40
and so on ...
hope u understand


Thank you so much!! I finally understand!!
Reply 15
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sarah5
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Original post by badmathkid
Thank you so much!! I finally understand!!


okay for the second question is the same idea
width*fd=k*frequency
they gave you the area and the frequency you have to find k
and then use k to find the frequency to other weights


I really like histograms every question has the same idea
so dont worry if you understand this !
<3 and good luck with your exam
Original post by sarah5
okay for the second question is the same idea
width*fd=k*frequency
they gave you the area and the frequency you have to find k
and then use k to find the frequency to other weights


I really like histograms every question has the same idea
so dont worry if you understand this !
<3 and good luck with your exam


Thanks so much! You're a life saver!! It's hard to remember and gets confusing sometimes. Thank you so much again! :smile:
F.d x Class width

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