thank you!
Jeph Herrin wrote:
>
> Prob(rain) = 7/120
> Prob(no rain) = 113/120
>
> X=days it rains on hat
>
> Prob(X=3)=c(4,3)*(7/120)^3*(113/120)^1
> =4*0.0001985*0.94
> =0.0007477
>
>
> not much chance!
>
>
> Richard Goldstein wrote:
>> it's been a long time since I thought about questions like this, but, as
>> a lead-in to a study, a client has asked the following question which he
>> thinks he understands and says is related to where he wants to go:
>>
>> during a consecutive period of 120 days, if it rains on 7 days and my
>> client wears a hat on 4 days (these are independent of any knowledge of
>> the weather), what is the probability that it will rain on 3 of the days
>> on which he is wearing a hat?
>>
>> my client swears that this is not a homework problem for him or his wife
>> or one of their kids!
>>
>> Rich
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