geeeeek
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#1
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#1
How do you calculate the median from a set of grouped data in a cumulative frequency table? Pls give an example and steps. Thanks
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Fallen99
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#2
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#2
(Original post by geeeeek)
How do you calculate the median from a set of grouped data in a cumulative frequency table? Pls give an example and steps. Thanks
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geeeeek
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#3
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#3
i used this and it still didnt work? idk why. pls explain
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Chittesh14
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#4
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#4
It usually doesn't work like that, you should just draw the graph. I researched for hours, didn't find nothing. You post some unusual questions haha :P, just saying, it's not bad . You either draw the graph or just guess it using this method, in my opinion:

(Total number of values +1 / 2) = median is in those values.

So let's say there are 10 cucumbers and we are finding the length of them.

The median length will be in the 4th or 5th cucumber.

It's hard to explain.
Just read this article, solution - Example 3:

http://www.cimt.plymouth.ac.uk/proje...ok9/bk9_16.pdf

Try reading the whole thing if possible.
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Fallen99
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#5
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#5
(Original post by Chittesh14)
It usually doesn't work like that, you should just draw the graph. I researched for hours, didn't find nothing. You post some unusual questions haha :P, just saying, it's not bad . You either draw the graph or just guess it using this method, in my opinion:

(Total number of values +1 / 2) = median is in those values.

So let's say there are 10 cucumbers and we are finding the length of them.

The median length will be in the 4th or 5th cucumber.

It's hard to explain.
Just read this article, solution - Example 3:

http://www.cimt.plymouth.ac.uk/proje...ok9/bk9_16.pdf

Try reading the whole thing if possible.
I find it easier to do with a graph and u r right it is hard to explain
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geeeeek
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#6
Report Thread starter 6 years ago
#6
What if I give you guys an example????

Number of tunes -----Number of weeks--------- Cumulative frequency

0-3 -----------------------------10--------------------
4-7 ------------------------------8--------------------
8-11----------------------------- 5----------------------
12-15 ---------------------------11---------------------
16-19----------------------------14--------------------




You are supposed to fill in the cumulative frequency, then calculate the median from this data. I already know how to calculate the cumulative frequency, but pls explain the next steps and how you got your answers.
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Chittesh14
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#7
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#7
(Original post by geeeeek)
What if I give you guys an example????

Number of tunes Number of weeks Cumulative frequency

0-3 10
4-7 8
8-11 5
12-15 11
16-19 14

You are supposed to fill in the cumulative frequency, then calculate the median from this data. I already know how to calculate the cumulative frequency, but pls explain the next steps and how you got your answers.
Can you please post the full question or take a photo? Also, make it in a table, at the moment, the information seems to be unclear. What is the whole question? Like, the question doesn't really make sense. The number of tunes played by students in 48 weeks?
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geeeeek
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#8
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#8
loool i just seen this. I edited it for you, hope it helps. And the no. of tunes is the grouped data and the number of weeks is the frequency
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Chittesh14
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#9
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#9
(Original post by geeeeek)
loool i just seen this. I edited it for you, hope it helps. And the no. of tunes is the grouped data and the number of weeks is the frequency
I understood it the first time, but just couldn't figure out what the information actually displayed haha. Nevertheless, I'll get back to you onto this, a bit busy at the moment, try drawing the graph first of all, get an answer to it. I'll draw a graph too in a while, see if our answers match from the graph's median? Then, we'll discuss how to work it out from the table.
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Dave1999
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#10
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#10
You add the frequencies together to get the total cumulative frequency, in your example:
10+8+5+11+14 = 48
You can then +1 to give 49 (when there's an odd number of results the median is the middle number)
You then divide your 49 by 2:
49/2 = 24.5
You then look down the cumulative frequency column and find out which group this number lies in, in this example the median lies within group 12-15.
If you want to draw a cumulative frequency graph for a more accurate answer you read off the cumulative frequency axis from 24.5 (again, middle ***. frequency) then where this intersects with the curve you read down to the x axis where the groups are shown and that will give you your more accurate median (it will show you exactly which number), it will be towards the lower end of the group (maybe 12?).
Hope this helps, there's probably some youtube videos on it if you have a look.
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Chittesh14
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#11
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#11
(Original post by Dave1999)
You add the frequencies together to get the total cumulative frequency, in your example:
10+8+5+11+14 = 48
You can then +1 to give 49 (when there's an odd number of results the median is the middle number)
You then divide your 49 by 2:
49/2 = 24.5
You then look down the cumulative frequency column and find out which group this number lies in, in this example the median lies within group 12-15.
If you want to draw a cumulative frequency graph for a more accurate answer you read off the cumulative frequency axis from 24.5 (again, middle ***. frequency) then where this intersects with the curve you read down to the x axis where the groups are shown and that will give you your more accurate median (it will show you exactly which number), it will be towards the lower end of the group (maybe 12?).
Hope this helps, there's probably some youtube videos on it if you have a look.
Yeah, that's exactly what I was saying . Thanks for explaining it in a detailed way, I'm sure this will help him better . Furthermore, the only reason I didn't explain it properly is because he wanted to find the median which is not possible, it'll be 12-15, it could be: 12,13,14 or 15 which is why we can only guess it through the table and we cannot answer his question. The cumulative frequency graph is the best way . I'm pretty sure his question is asking "What is the median group for this cumulative frequency table?" Maybe he's just forgotten or misunderstanding the question, reason being why we are all struggling to answer it.
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Dave1999
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#12
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#12
(Original post by Chittesh14)
Yeah, that's exactly what I was saying . Thanks for explaining it in a detailed way, I'm sure this will help him better . Furthermore, the only reason I didn't explain it properly is because he wanted to find the median which is not possible, it'll be 12-15, it could be: 12,13,14 or 15 which is why we can only guess it through the table and we cannot answer his question. The cumulative frequency graph is the best way . I'm pretty sure his question is asking "What is the median group for this cumulative frequency table?" Maybe he's just forgotten or misunderstanding the question, reason being why we are all struggling to answer it.
Maybe
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