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# S2 - Hypothesis Testing (Quick Question) Watch

1. Hey guys.

Suppose you're doing a hypothesis test on an Edexcel S2 exam question, and it involves the Poisson distribution.

My question generally is, what is the rule about the value of lambda in your hypothesis?

Don't get me wrong I understand how it all works but suppose we have this scenario:

A manufacturer produces 4 defective components out of every 100 or something. Now, you do a hypothesis test involving 300 samples.

Do I put H0 as lambda = 4 or H0 as lambda = 12.

I've looked at mark schemes and honestly, they seem to swap it about all the time!

Sometimes they say allow lambda = something, and the mean = something else. So I tried to stick to a certain rule but did another past paper, and they were swapped around. :s

Can anyone please tell me what I should write in these types of questions? Thanks.

EDIT: This thread is a duplicate guys, sorry. For some reason this one went to mod approval or something.
2. (Original post by Hamburglar)
Hey guys.

Suppose you're doing a hypothesis test on an Edexcel S2 exam question, and it involves the Poisson distribution.

My question generally is, what is the rule about the value of lambda in your hypothesis?

Don't get me wrong I understand how it all works but suppose we have this scenario:

A manufacturer produces 4 defective components out of every 100 or something. Now, you do a hypothesis test involving 300 samples.

Do I put H0 as lambda = 4 or H0 as lambda = 12.

I've looked at mark schemes and honestly, they seem to swap it about all the time!

Sometimes they say allow lambda = something, and the mean = something else. So I tried to stick to a certain rule but did another past paper, and they were swapped around. :s

Can anyone please tell me what I should write in these types of questions? Thanks.

EDIT: This thread is a duplicate guys, sorry. For some reason this one went to mod approval or something.
Just spotted that but I'll answer anyway...

You are confusing yourself I believe. No such ambiguity would ever arise and the reason is that that that particular problem gives you a proportion and so, short of making approximations, you must model it as having a binomial distribution Tip: Revise when to use each one!

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