Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta

Bayes theorem / conditional probability help watch

    • Thread Starter
    Offline

    2
    ReputationRep:
    In Scotland the household incomes of the population is 50% of the households are considered low income, 40% are considered moderate income, and 10%
    are considered high income. The probability that a low income household will
    evade tax is 0.1. The corresponding probabilities for moderate income and high income households are
    0.2 and 0.6 , respectively.

    1. What is the probability that a randomly chosen household is a low income tax evader
    2. What proportion of tax evaders have a low income?

    I have set P(L) = 0.50, P(M) = 0.40, P(H) = 0.10 along with P(T|L) = 0.10, P(T|M) = 0.20 and P(T|H) = 0.6



    For part 1) are they asking for P(LnT) or are they literally asking me to regurgiate information provided within the text?

    Also for part 2.) would it be the same as doing P(LnT) / P(t) * 100 ?
    • Very Important Poster
    Online

    21
    ReputationRep:
    Very Important Poster
    (Original post by TwiMaster)
    In Scotland the household incomes of the population is 50% of the households are considered low income, 40% are considered moderate income, and 10%
    are considered high income. The probability that a low income household will
    evade tax is 0.1. The corresponding probabilities for moderate income and high income households are
    0.2 and 0.6 , respectively.

    1. What is the probability that a randomly chosen household is a low income tax evader
    2. What proportion of tax evaders have a low income?

    I have set P(L) = 0.50, P(M) = 0.40, P(H) = 0.10 along with P(T|L) = 0.10, P(T|M) = 0.20 and P(T|H) = 0.6



    For part 1) are they asking for P(LnT) or are they literally asking me to regurgiate information provided within the text?

    Also for part 2.) would it be the same as doing P(LnT) / P(t) * 100 ?
    For part 1) I also think it is P(LnT).

    For part 2) think about how you can use Bayes' Theorem and what you need to find out. The denominator should end up being P(T) by law of total probablity and your numerator needs to be rewritten but otherwise should be correct.
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by SeanFM)
    For part 1) I also think it is P(LnT).

    For part 2) think about how you can use Bayes' Theorem and what you need to find out. The denominator should end up being P(T) by law of total probablity and your numerator needs to be rewritten but otherwise should be correct.
    Hmm, how should the numerator be rewritten?
    • Very Important Poster
    Online

    21
    ReputationRep:
    Very Important Poster
    (Original post by TwiMaster)
    Hmm, how should the numerator be rewritten?
    Well, what is part 2 asking you to find? P(.... given ....). So using Bayes' Theorem..

    Though thinking about it your numerator is fine, it's just not clear how you got there.
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by SeanFM)
    Well, what is part 2 asking you to find? P(.... given ....). So using Bayes' Theorem..
    P(T|L) im assuming
    • Very Important Poster
    Online

    21
    ReputationRep:
    Very Important Poster
    (Original post by TwiMaster)
    P(T|L) im assuming
    Other way round

    But I think your numerator is fine, you just didn't show your steps to getting to that equation.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: November 7, 2015
Poll
Do you agree with the proposed ban on plastic straws and cotton buds?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

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