Qualification > Math
S1 and S2 DOUBTS HERE!!!!
Arthur Bon Zavi:
--- Quote ---4. Questions 6b and c of January 2008 on this link:
http://www.xtremepapers.net/Edexcel/Advanced%20Level/Mathematics/2008%20Jan/6683_01_que_20080115.pdf
--- End quote ---
(6) (b)
Weights between 190 and 210 are 60 %.
Now 60 % is equal to 0.6 of the probability right. So find out the value of si (0.6) which is equal to 0.7257 .
Now you know the formula :
X - mean
Z = -------------
standard deviation
Let standard deviation be s.
So :
210 - 200 190 - 200
------------ - ------------ = 0.7257
s s
10 - (-10)
----------- = 0.7257
s
20 = 0.7257s
s = 20/(0.7257)
standard deviation = 27.55959763 (or 27.56)
(c)
Use the same formula of normal distribution.
If you will use the original value of standard deviation (that is 27.55959763 and not 27.56), you will be benefited.
180 - 200
---------------
27.55959763
= si (-0.7257)
= 1 - { si (0.726) }
= 1 - 0.766
= 0.234
So 0.234 is the probability that the customer will complain.
Arthur Bon Zavi:
--- Quote ---With explanation please, I have the marking scheme, so I know the answers, but I can't understand the working/how to do it! :/
Thanks alot! :)
--- End quote ---
Can you please provide all 4 marking schemes please ? Here itself.
Arthur Bon Zavi:
What Master_Key told is correct. Sorry it just got deleted, while I was playing with my slow internet around. :D
Firstly, don't forget to add (+0.5) if you are finding probability of a greater than number like in your 3rd question it was more than 53 kg, otherwise you may get a penalty (loss of marks) - I don't know whether the same is practised in ED-EXCEL or not.
Lastly, if you don't want to forget to keep in (+0.5), just apply the formula without adding (+0.5):
1 - { si (<=X) }
Alpha:
--- Quote from: The Secret on April 12, 2011, 07:25:32 pm ---I'm sorry, your answers are wrong, check Fidato's post above for the right answer.
--- End quote ---
Apologies. I wasn't in my right state of mind. -.-
**RoRo**:
--- Quote from: Fidato on April 13, 2011, 11:52:01 am ---Here they follow.
Done.
After 3 games Rohit has scored 6.
2 games are left and he has to get 4 points or more to win the prize.
List all the outcomes of the points he can get (see the image below).
You can see that there are 16 possible outcomes and six of which fetch him 4 points or more.
You know that :
P(0) = 0.4
P(1) = 0.3
P(2) = 0.2
P(3) = 0.1
So to win a price he should get points with the outcomes as follows (as circled in image).
{ (1,3) (2,2) (2,3) (3,1)(3,2) (3,3) }
Multiply and add the probabilities :
(0.3 X 0.1) + (0.2 X 0.2) + (0.2 X 0.1) + (0.1 X 0.3) + (0.1 X 0.2) + (0.1 X 0.1)
= 0.03 + 0.04 + 0.02 + 0.03 + 0.02 + 0.01
= 0.15
--- End quote ---
This one's right and I understood it, thank you! :)
I'm sorry, the link for the marking scheme for this paper is not opening now! :/
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