You are Here: Home >< Maths

# Help I can't understand the difference between the two types of probability😩

Announcements Posted on
Last day to win £100 of Amazon vouchers - don't miss out! Take our quick survey to enter 24-10-2016
1. I'd really appreciate it if someone could explain the difference between the types of probability in maths? 😊
2. (Original post by Bitsy)
I'd really appreciate it if someone could explain the difference between the types of probability in maths? 😊
You're going to have to be a bit more specific

Do you have a particular question that you're stuck with?
3. You need to elaborate.
4. This Q is probably GCSE in which case you are having to deal with "Mutually exclusive" events where only one can happen. e.g. select a sock and it is either blue or red, not both. This kind of question requires you to add together probabilities to answer questions of the form "What is the probability of event A OR event B happening.

You also have "Independent" events where you ask about two events that might both occur. e.g. Throw a die twice and you might get 6, 6. This allows us to ask what is the probability of Event A AND Event B happening. e.g. What is the probability that you select a red top AND a blue sock

The most tricky GCSE questions often involve Tree diagrams and distinguishing with and without replacement but it is the interpretation that is most tricky and this question was well publicised. It is possible for "Mutually exclusive" events and
"Independent" events to be combined in the same long question.

If you are doing A-level then you may also have to do Bayesian probability which is more tricky to understand and involves the sample space being altered by a prior event.
5. if it is GCSE then OP is most probably referring to With Replacement vs Without Replacement ?
6. (Original post by nerak99)
This Q is probably GCSE in which case you are having to deal with "Mutually exclusive" events where only one can happen. e.g. select a sock and it is either blue or red, not both. This kind of question requires you to add together probabilities to answer questions of the form "What is the probability of event A OR event B happening.
(Original post by the bear)
if it is GCSE then OP is most probably referring to With Replacement vs Without Replacement ?
7. (Original post by XOR_)
what are the chances of that happening ?

8. (Original post by nerak99)
This Q is probably GCSE in which case you are having to deal with "Mutually exclusive" events where only one can happen. e.g. select a sock and it is either blue or red, not both. This kind of question requires you to add together probabilities to answer questions of the form "What is the probability of event A OR event B happening.

You also have "Independent" events where you ask about two events that might both occur. e.g. Throw a die twice and you might get 6, 6. This allows us to ask what is the probability of Event A AND Event B happening. e.g. What is the probability that you select a red top AND a blue sock

The most tricky GCSE questions often involve Tree diagrams and distinguishing with and without replacement but it is the interpretation that is most tricky and this question was well publicised. It is possible for "Mutually exclusive" events and
"Independent" events to be combined in the same long question.

If you are doing A-level then you may also have to do Bayesian probability which is more tricky to understand and involves the sample space being altered by a prior event.
Thanks 😊 (Yeah I am IGCSE level sorry I didn't specify)

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: April 26, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### How does exam reform affect you?

From GCSE to A level, it's all changing

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams