Qualification > Math
CIE statistic2 doubts! Help please
Tohru Kyo Sohma:
--- Quote from: ~Alpha on July 31, 2011, 12:10:06 pm ---Oh yes, I forgot this part. ;D
It's ln, not In. Log e to the base of e. See on a scientific calculator. Chapter ref.: logarithms. :)
http://www.chem.tamu.edu/class/fyp/mathrev/mr-log.html
--- End quote ---
ok
i did question 8....i got part a but not part b
this is how i did it
(a)1 sec=1 particle
therefore for 4 sec =4 particles
X~Po(4)
P(X=0 or 1)=e^-4 +e^-4 *4
=0.091
(b)P(X=0 or 1)=0.8
e^-n +e^-n *n =0.8
this is all i got
Alpha:
--- Quote from: Tohru Kyo Sohma on July 31, 2011, 12:23:45 pm ---ok
i did question 8....i got part a but not part b
this is how i did it
(a)1 sec=1 particle
therefore for 4 sec =4 particles
X~Po(4)
P(X=0 or 1)=e^-4 +e^-4 *4
=0.091
(b)P(X=0 or 1)=0.8
e^-n +e^-n *n =0.8
this is all i got
--- End quote ---
Hm... yes, I got that too. You can use iteration for that, but I don't think it's used in Stats, I never did, at least. :-\
I'll think about another way to do it and let you know.
Tohru Kyo Sohma:
--- Quote from: ~Alpha on July 31, 2011, 02:22:51 pm ---Hm... yes, I got that too. You can use iteration for that, but I don't think it's used in Stats, I never did, at least. :-\
I'll think about another way to do it and let you know.
--- End quote ---
interation?
never heard of it
thanks alot alpha for your help!
Alpha:
--- Quote from: Tohru Kyo Sohma on July 31, 2011, 02:33:37 pm ---interation?
never heard of it
thanks alot alpha for your help!
--- End quote ---
Iteration. It's making n subject, and replacing with subsequent values obtained.
http://www.projectalevel.co.uk/as_a2_maths/iteration
But no, I don't think it can be used here... there must be some other way out.
You're always welcome. :)
Tohru Kyo Sohma:
i have a few doubts here
Qns.1 the number of goals scored by a football team during a season gave the following results.
_____________________________________________________
Number of goals per match 0 1 2 3 4 5 6 7
Number of matches 5 19 9 5 2 1 0 1
_____________________________________________________
Calculate the mean and variance of the distribution.Calculate also the relative frequencies and the theoretical probabilities for x=0,1,2,3,4,5,6,>=7 ,assuming a Poisson distribution with the same mean.Do you think, in light of your calculations, that the Poisson distribution provides a suitable model for the number of goals per match?
Qns.2 The number of cars passing a given point in 100 10-second intervals was observed as follows.
_________________________________________
Number of cars 0 1 2 3 4 5
Number of intervals 47 33 16 3 0 1
_________________________________________
Do you think that a Poisson distribution is a suitable model?
Qns.3 When a large number of flashlights leaving a factory is inspected it is found that the bulb is faulty in 1% of the flashlights and the switch is
faulty in 1.5% of them.Assuming that the faults occur independently and at random,find
(a)the probability that a sample of 10 flashlights contain no flashlights with a faulty bulb,
(b)the probability that a sample of 80 flashlights contains at least one flashlight with both a defective bulb and a defective switch,
(c)the probability that a sample of 80 flashlights contains more than two defective flashlights.
so these are my doubts
the answers to them are below
1. 1.71,1.97;
0.12,0.45,0.21,0.12,0.05,0.02,0,0.02,0.18,0.31,0.26,0.15,0.06,0.02,0.01,0.002
Poisson distribution is not suitable
2. mean=0.79,variance=0.87
theoretical probabilities 0.45,0.36,0.14,0.04,0.01,0.001. Yes.
3.(a)0.904 (b)0.0119 (c)0.320
this question below,i know how to do but im a lttle confused since poisson distribution is not possible
qns.there are 5000 students in a university.Calculate the probabilty that exactly 15 of them have their birthday on 1 january, by using a suitable Poisson distribution
here i calculate np>5 therefore poisson distribution is not possible
but the text gives answer for it 0.0965
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version