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    6 /C During a garden fete cups of tea are thought to be sold at a rate of 2 every minute. To test this, the number of cups of tea sold suring a random 30 minute interval i srecorded.

    Find the critical region for a two tailed hypothesis test that the number of cups of tea sold occurs at a rate of 2 every minute. The probability in each tail should be as close to 2.5% as possible

    Ok im really confused it says during a random 30 minute interval so i did 30 x 2 =60 and put lander=60 and tried to use the normal which didnt work out. So i looked at their solution and they got lander=2 and used that to find the critical regions. What im confused about is why have they completely ignored the 30 minute interval bit???
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    (Original post by Ramin Gorji)
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    Your reasoning seems sound, but without seeing their actual question and solution I can't be certain.
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    I also need help with this q pls.

    Q. During a garden fete cups of tea are sold at a rate of 2 every minute. To test this, the no. of cups of tea sold during a random 30 minute interval is recorded,.
    Find the critical region for a 2 tailed hypothesis that the no. of cups of tea sold occurs at a rate of 2 every minute. The probability in each tail should be as close as possible to 2.5 %.

    Book answer: critical region xis greater than or equal to 6. But why is the actual significance 0.0166.

    Please could someone very kind teach me the method for this (perhaps using a different example and I can do it on my own? So you're not actually doing my homework for me!). Also don't understand how the 'actual significance' has been calculated.

    Thank you
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    To Ramin G. Also stuck on it, but it says 'that the no of cups occrs at a rate of 2 per minute' so isn;t it saying lam. is 2? or am I wrong?
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    (Original post by vet_hopeful!_worried)
    I also need help with this q pls.

    Q. During a garden fete cups of tea are sold at a rate of 2 every minute. To test this, the no. of cups of tea sold during a random 30 minute interval is recorded,.
    Find the critical region for a 2 tailed hypothesis that the no. of cups of tea sold occurs at a rate of 2 every minute. The probability in each tail should be as close as possible to 2.5 %.

    Book answer: critical region xis greater than or equal to 6. But why is the actual significance 0.0166.

    Please could someone very kind teach me the method for this (perhaps using a different example and I can do it on my own? So you're not actually doing my homework for me!). Also don't understand how the 'actual significance' has been calculated.

    Thank you
    As near as I can tell (best guess), they have taken a random 1 minute interval, rather than 30 minute interval they claimed.

    Then checking the Poisson distribution with lambda = 2, then the closest value to 2.5% (i.e. 0.975 at the upper end) is 0.9834, given a tail of 1-0.9834 = 0.0166 for values of >=6.

    God knows how they worked out the bottom end though.
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    Thank you so much. I think they ignore the bottom end, as it is larger than 0.025, that is what I'm 'guessing'. thanks again
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    It's badly worded. It would have been better to state that...

    "The probability in each tail should be at most 2.5%"...instead of "as close as possible to".

    This would result in exactly one critical region from a 2-tailed test which is very unusual for an S2 question.
 
 
 
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