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

    2
    ReputationRep:
    Name:  Probability HW1, Q3.png
Views: 169
Size:  29.7 KB


    I've been sat here for an hour now trying to make sense of these questions, but I really don't have a clue. A bit of help would be much appreciated right now
    • Study Helper
    Offline

    15
    Study Helper
    (Original post by TwiMaster)
    Name:  Probability HW1, Q3.png
Views: 169
Size:  29.7 KB


    I've been sat here for an hour now trying to make sense of these questions, but I really don't have a clue. A bit of help would be much appreciated right now
    What's causing the problem? Is it the notation for the set/event definitions?
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by ghostwalker)
    What's causing the problem? Is it the notation for the set/event definitions?
    No, I'm okay with understanding the sets in this case. I just can't get my head around the questions
    • Thread Starter
    Offline

    2
    ReputationRep:
    Guys, how would I answer parts a.) and b.) ?
    • Community Assistant
    • Study Helper
    Offline

    20
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by TwiMaster)
    Name:  Probability HW1, Q3.png
Views: 169
Size:  29.7 KB


    I've been sat here for an hour now trying to make sense of these questions, but I really don't have a clue. A bit of help would be much appreciated right now
    Writing the sets in a simpler way may help:

    A = {female residents}
    B = {non-smoking residents}
    C = {non-over weight residents}

    Now what does A ∩ B ∩ C mean?
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by notnek)
    Writing the sets in a simpler way may help:

    A = {female residents}
    B = {non-smoking residents}
    C = {non-over weight residents}

    Now what does A ∩ B ∩ C mean?
    Female residents who are non-smoking and are not overweight
    • Community Assistant
    • Study Helper
    Offline

    20
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by TwiMaster)
    Female residents who are non-smoking and are not overweight
    Correct. So how can that set be equal to the set of female residents?
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by notnek)
    Correct. So how can that set be equal to the set of female residents?
    I still don't get how they could be equal to one-another
    • Community Assistant
    • Study Helper
    Offline

    20
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by TwiMaster)
    I still don't get how they could be equal to one-another
    Here's an example:

    A = {a, b, c}
    B = {a, b, c, d}
    C = {a, b, c, d, e}

    A ∩ B ∩ C = {a, b, c} = A

    Let me know if you don't understand this example.

    Think about what had to happen in this question for A ∩ B ∩ C to be equal to A. Then try to apply this idea to your question.
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by notnek)
    Here's an example:

    A = {a, b, c}
    B = {a, b, c, d}
    C = {a, b, c, d, e}

    A ∩ B ∩ C = {a, b, c} = A

    Let me know if you don't understand this example.

    Think about what had to happen in this question for A ∩ B ∩ C to be equal to A. Then try to apply this idea to your question.
    From what I can see from your example, A is a subset of both B and C thus meaning that all the elements in A are also contained in B and C so A ∩ B ∩ C = A
    • Community Assistant
    • Study Helper
    Offline

    20
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by TwiMaster)
    From what I can see from your example, A is a subset of both B and C thus meaning that all the elements in A are also contained in B and C so A ∩ B ∩ C = A
    That's correct and this as it is may be OK as an answer.

    But thinking about your specific question : what does this tell you about all the female residents?
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by notnek)
    That's correct and this as it is may be OK as an answer.

    But thinking about your specific question : what does this tell you about all the female residents?
    All the females are neither smokers or overweight?
    • Community Assistant
    • Study Helper
    Offline

    20
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by TwiMaster)
    All the females are neither smokers or overweight?
    Correct

    Have another go at the next question and post your ideas if you are still stuck.
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by notnek)
    Correct

    Have another go at the next question and post your ideas if you are still stuck.
    Thank you! I definitely wouldn't have gotten that one

    I think part b.) is implying that those who are overweight do not smoke
    • Community Assistant
    • Study Helper
    Offline

    20
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by TwiMaster)
    Thank you! I definitely wouldn't have gotten that one

    I think part b.) is implying that those who are overweight do not smoke
    Correct again.

    Is c) OK?
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by notnek)
    Correct again.

    Is c) OK?
    Yay, Is c.) saying that being male is independent of being a smoker?
    • Thread Starter
    Offline

    2
    ReputationRep:
    Does anybody know how to answer part c.) ?
    • Study Helper
    Offline

    15
    Study Helper
    (Original post by TwiMaster)
    Yay, Is c.) saying that being male is independent of being a smoker?
    I presume you mean part d).

    'Fraid not. And you want to be careful using the terms "independent" and similar, as they have a specific meaning in probability and statistics.

    You've identified that one set represents male residents, and one represents non-smokers. What's the equality sign telling you?
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: October 26, 2015
Poll
Do you like carrot cake?
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.