Oh? I found that to be fairly fine, just took a bit of work, I think it was actually the second part of the first question that threw me; took me a while to work out how to do it. :P

Reply 5

ahannah

2

Original post by WhisperingTide

Oh? I found that to be fairly fine, just took a bit of work, I think it was actually the second part of the first question that threw me; took me a while to work out how to do it. :P

what did you do for it? Haha I'm not sure if I did that right... i worked out P(X=4) and P(Y=4) using the formula for poisson distribution and multiplied them...

Reply 6

WhisperingTide

OP

10

Original post by ahannah

what did you do for it? Haha I'm not sure if I did that right... i worked out P(X=4) and P(Y=4) using the formula for poisson distribution and multiplied them...

Well, I got E(W) = 6 and Var(W) = 36
Made that into a Normal: N~( 6 , 36 )
And continuity corrected either side, giving: P(3.5 < 4 < 4.5)
Not sure if that's right, though. >.> What did you get as an answer?

Reply 7

ahannah

2

Original post by WhisperingTide

Well, I got E(W) = 6 and Var(W) = 36
Made that into a Normal: N~( 6 , 36 )
And continuity corrected either side, giving: P(3.5 < 4 < 4.5)
Not sure if that's right, though. >.> What did you get as an answer?

hmm why would you make a normal approximation? It wasn't a large enough mean value surely? I can't remember, I think it was around 0.015?

Reply 8

WhisperingTide

OP

10

Original post by ahannah

hmm why would you make a normal approximation? It wasn't a large enough mean value surely? I can't remember, I think it was around 0.015?

I seem to recall combinations of observations of random variables are normally distributed by default, or something like that. Actually, I think I got around that anyway, so that's awesome! :smile:

Reply 9

roganjosh4444

1

Original post by WhisperingTide

Well, I got E(W) = 6 and Var(W) = 36
Made that into a Normal: N~( 6 , 36 )
And continuity corrected either side, giving: P(3.5 < 4 < 4.5)
Not sure if that's right, though. >.> What did you get as an answer?

I got the same values for E(W) and Var(W), but for the second part I multiplied the two poisson values to get Po~(6), and then did P(W≥4) - P(W≥5), but that was just a blind shot in the dark! Hopefully someone will be able to upload the paper on here.