Turn on thread page Beta
    • Thread Starter

    Hi all

    The question goes like this:
    A single observation x is to be taken from a Poison distribution with paramater A, This observation is to be used to test H0:A=7 against H1:A =/ 7.
    Using a 5% sig. level, find the CR for this test assuming that the pro. of rejecting in either tail is as close as possible to 2.5%

    What I have got is:
    P(X<=1)=0.0073 and P(X>=14)=1-0.9872=0.0128
    CR: X<=1 or X>=14

    But what the mark scheme gives is:
    CR X<=2 or X>=13

    I see they try to make Critical Level closer to 5% overall, but in the exam how do I know where to change? Or Would I get all marks with my present answer? Please let me know asap, thanks.

    If they say 'as close as possible' (as above) then you have to take values that are as close as the sig level as possible, regardless of whether they're over the level.

    If they simply ask for the critical regions, then you would have to do as you did, and take the values of X giving just less than the sig level.
    • Thread Starter

    flipping hell, can I increase one way only to make it bigger? Or Do I have to increase both? What is the rule?

    What do you mean increase? :confused:

    the reason why it is X<=2 is cos it must include 0.025... X<=1 does not include it
    • Thread Starter

    Thanks guys.
The home of Results and Clearing


people online now


students helped last year

University open days

  1. Keele University
    General Open Day Undergraduate
    Sun, 19 Aug '18
  2. University of Melbourne
    Open Day Undergraduate
    Sun, 19 Aug '18
  3. Sheffield Hallam University
    City Campus Undergraduate
    Tue, 21 Aug '18
A-level students - how do you feel about your results?
Help with your A-levels

All the essentials

The adventure begins mug

Student life: what to expect

What it's really like going to uni


Essay expert

Learn to write like a pro with our ultimate essay guide.

Uni match

Uni match

Our tool will help you find the perfect course for you

Study planner

Create a study plan

Get your head around what you need to do and when with the study planner tool.

Study planner

Resources by subject

Everything from mind maps to class notes.

Hands typing

Degrees without fees

Discover more about degree-level apprenticeships.

A student doing homework

Study tips from A* students

Students who got top grades in their A-levels share their secrets

Study help links and info

Can you help? Study help unanswered threadsRules and posting guidelines

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.