WST01/01 (Edexcel) IAL S1 January 2021 IAL Q4 Discrete Random Variables

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[sitaraanwer]

For the last question it’s the probability that w = y not x wouldn’t the answer be different then?

[ayshakhatun]

I have a question.
For the mean value when, it's discreet uniform distribution aren't we supposed to find the
E(X) by this formula?
E(X)= n+1/2 ?

and for Var (X) aren't we suppose to use this formula?
Var(X) = (n+1)(n-1)/12 ?

[yutosagara]

Aren’t we have to use the n+1/2 for e(x) and (n-1)(n+1)/12 for var(x) ? As it is discrete uniform distribution

[venos]

How to did you a^2Var(X) from Var(W) ?

[sarahstocks]

i dont understand how u went from E(x)=E(ax+b) to aE(x)+b

[rahmathali]

Part c u got the value of a wrong a=9/25 u changed that to 3/5 for some reason which is why u got the entire process after that wrong