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# Statistics AS maths help watch

"A group of 60 children were each asked to choose an integer value between 1 and 9 inclusive. Their choices are summarised in the table below:

Value Chosen | Number of children
1 | 3
2 | 4
3 | 5
4 | 10
5 | 12
6 | 13
7 | 7
8 | 4
9 | 2

Calculate the mean.

I would like to know why the mean is worked out as [sum of x * Frequency] / frequency and not [sum of x]/n ... I thought that this looked like discrete data and not continuous/ grouped data so can't understand why we are using the former formula... Sorry if I'm missing something basic. Thanks again
2. number of children = f, so it needs to be sum of xf divided by the sum of f, that's as well as I can explain it, sorry if it isn't much use
3. (Original post by phishingrhod)
number of children = f, so it needs to be sum of xf divided by the sum of f, that's as well as I can explain it, sorry if it isn't much use
Hi - thanks so much for your quick response. Just wondering though- which wouldn't it be 60/9 = 6.7 (1dp)? just a tad confused as the stats book suggests you should only use the xf/f formula for continuous/ grouped data - and this is discrete data - unless I'm missing something basic?
4. tbh, I'm not sure as to why, but now whenever I see this sort of question, I go for the xf/f by instinct, but I suppose it's the amount (/frequency) of children picking a certain number, which means that the mean number chosen would be 303/60=5.05

Best bet is, if a particular group of people are CHOOSING something, take what they choose as being x, and the number of times that x is chosen is f, that's what seems to work for me

sorry if this hasn't been much help, again
5. (Original post by phishingrhod)
tbh, I'm not sure as to why, but now whenever I see this sort of question, I go for the xf/f by instinct, but I suppose it's the amount (/frequency) of children picking a certain number, which means that the mean number chosen would be 303/60=5.05

Best bet is, if a particular group of people are CHOOSING something, take what they choose as being x, and the number of times that x is chosen is f, that's what seems to work for me

sorry if this hasn't been much help, again
Great, thank you so much

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