This discussion is closed.
#1
hey...the june 2003 paper has a really funny question and i cant find the markscheme anywhere. any help much appreciated!

3. In a town, 30% of residents listen to the local radio station. Four residents are chosen at random
a) state teh distribution (I said Binomial, with n=4 and p=0.3)
b) on graph paper, draw the probability distribution of x
how do i do this?! never seen anything like it before

thanks x
0
14 years ago
#2
basically draw the graph of probabilitiy (y-axis) against no. of resident
its a silly stupid question and is pointless
0
#3
as in 0.3 on y axis and 4 on x axis and the two points joined so the graph is like a triangle?
0
14 years ago
#4
no no... u do the following
X=no.of residnents listening to radio X-B(4,0.3)
calculate the probabilities 0f
P(X=0) , P(X=1) , P(X=2), P(X=3) and P(X=4)
now plot these porbabilites againt 1 ,2 , 3 ,4 respectivley but join points
does that make sense?
0
14 years ago
#5
sorry i mean dont join the points
0
#6
oo yes it does...so y axis has things like the tables e.g. 0.0237 (random example) and x axis has 0,1,2,3,4

that right?

and kind of like a scatter diagram as in no line joining them all up?
0
14 years ago
#7
yes u are nearly there

but one thing to note that that i said dont join points BUT do joint numbers (1,2,3,4) with thier probabilities
0
#8
oo ok so u get lots of diagonal lines?

thanks for this! x
0
14 years ago
#9
u should get straight lines
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#10
as in diagonal from x axis to y axis i.e. 1 on x joined with prob of 1 on y
0
14 years ago
#11
horizontal lines goin from x axis directly up to the corresponding probablility

Can u tell me iff we'll get extra binomial tables since in s2 book there is only distribution available for n=5,10,20. So r we gonna get a booklet with probability distributions with variety of values for n?????
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#12
right thank u!

off to bed now
xx
0
14 years ago
#13
yes in the formula book u have n= 5,6,7,8,10,12,15,20,25,30......5 0 something like that
0
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