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# Edexcel (IAL): Statistics 1, WST01 (27th January 2016) watch

1. (Original post by WilsonDS)
For 6d), I don't understand how S.D decrease while there was no change in the mean value. I must be missing something...
Standard deviation is a measure of the *spread* of the data. If you add in two points that are closer to the mean than the others are (on average), you *decrease* the spread of the data and hence the standard dev.

Imagine the mean to be one line and if all the data lies on the line (horizontal line) then the spread is 0. If the data is spread top and bottom, the spread in increases. You can add a data point that is far away from the mean and a data point that is far below the mean that keeps the mean constant because they cancel each other out but increases the standard deviation because the data is more spread.
2. (Original post by Zacken)
Standard deviation is a measure of the *spread* of the data. If you add in two points that are closer to the mean than the others are (on average), you *decrease* the spread of the data and hence the standard dev.

Imagine the mean to be one line and if all the data lies on the line (horizontal line) then the spread is 0. If the data is spread top and bottom, the spread in increases. You can add a data point that is far away from the mean and a data point that is far below the mean that keeps the mean constant because they cancel each other out but increases the standard deviation because the data is more spread.
Thanks, I get it now.
There goes my mark then *sigh*
3. In Q2, last part, I assumed it is a given condition and without replacement. Thus, my ans was 0.25*0.24*0.5*3 / 0.75*0.74*0.73, it sounds weird lol, lost 3 marks anyway~
4. Does anyone have access to the S1 paper ? If someone does, please can you upload it as I need to see what marks I got
5. (Original post by Zacken)
..
You are an active member of the forum can you please tag/quote me in if you find S1 Model answers?

Thank you.
6. (Original post by Hamzah249)
You are an active member of the forum can you please tag/quote me in if you find S1 Model answers?

Thank you.
The person who usually does model answers will probably tag you himself, but if he doesn't, I will.
7. Is anyone sitting the S2 exam tomorrow?
Is anyone sitting the S2 exam tomorrow?
I am.
9. (Original post by Zacken)
I am.
Me too. Good luuck ! Is there a thread for that?
10. I am
Is anyone sitting the S2 exam tomorrow?
I am
Me too. Good luuck ! Is there a thread for that?
(Original post by Eyzel)
I am
Why don't one of you create a thread for it? I'll probably post my answers there tomorrow.
13. My exams are over, Good luck to all of you for upcoming exams.
14. (Original post by Zacken)
Why don't one of you create a thread for it? I'll probably post my answers there tomorrow.
Here it is
http://www.thestudentroom.co.uk/show....php?t=3858403
15. Yeah me too please. Thank you

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