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Probability S1

zed963

I pretty much hate this topic, I've no idea how to get over it.

I'm stuck on this question.

Reply 1

TenOfThem

Original post by zed963

I pretty much hate this topic, I've no idea how to get over it.

I'm stuck on this question.

70% of my responses to probability questions (S1) are Draw a Venn
The remaining 30% are Draw a Tree

This falls into the 70%

Reply 2

davros

Original post by TenOfThem

70% of my responses to probability questions (S1) are Draw a Venn
The remaining 30% are Draw a Tree

This falls into the 70%

Where would you fit the rest of us who prefer to do it algebraically from P(AnB) = P(A)P(B|A) etc? :biggrin:

Reply 3

TenOfThem

Original post by davros

Where would you fit the rest of us who prefer to do it algebraically from P(AnB) = P(A)P(B|A) etc? :biggrin:

I gave 100% of my responses - I can only do these questions from a position of understanding

I appreciate there are people who would advise differently - if posters seem to be going that way I tend to bow out

Reply 4

davros

Original post by TenOfThem

Out of interest, do you find that Venn diagrams actually help students with calculations, or are just a visual aid in seeing how things are broken up?

I only ask because there seem to be people on TSR who are quite happy drawing the Venn diagram, but can't then make the connection between the "pieces" and the relationship between separate probabilities.

Personally, I prefer to start with an unambiguous algebraic rule when proving things, and use a diagram just as an aillustration, but that's just my preference :smile:

Reply 5

TenOfThem

Original post by davros

Out of interest, do you find that Venn diagrams actually help students with calculations, or are just a visual aid in seeing how things are broken up?

I teach using them so my students understand the calculations

They also understand the rules because they can see where and why based on the Venn

I think my preference comes from my age - I hate "learning" any rules

Reply 6

Dylann

Original post by TenOfThem

70% of my responses to probability questions (S1) are Draw a Venn
The remaining 30% are Draw a Tree

This falls into the 70%

I disagree. I would use a tree for this.

Edit: I wouldn't use a tree or venn for this.

Posted from TSR Mobile

(edited 10 years ago)

Reply 7

TenOfThem

Original post by Dylann

I disagree.

How can you disagree - that is a fact

I would use a tree for this.

People have different approaches :smile:

Reply 8

Dylann

Original post by TenOfThem

How can you disagree - that is a fact

People have different approaches :smile:

'I would use a venn for this' I was disagreeing with that. But as I corrected myself, I wouldn't use either.

Posted from TSR Mobile

Reply 9

TenOfThem

Original post by Dylann

'I would use a venn for this' I was disagreeing with that.

Again, it is still a fact

But as I corrected myself, I wouldn't use either.

Again, people use different methods

Reply 10

Chicken.M.

Original post by TenOfThem

70% of my responses to probability questions (S1) are Draw a Venn
The remaining 30% are Draw a Tree

This falls into the 70%

This is the easiest way if you aren't that good at maths. Just draw a venn diagram and put in all the possibilities.

You'l have to find a common denominator though I think

Reply 11

TenOfThem

Original post by ChickenMadness

This is the easiest way if you aren't that good at maths. Just draw a venn diagram and put in all the possibilities.

You'l have to find a common denominator though I think

Well, there you go

I am not too bad at maths generally but I am not a Stats specialist so, I as I say, I go for understanding to supplement

Reply 12

Chicken.M.

Original post by TenOfThem

Well, there you go

I am not too bad at maths generally but I am not a Stats specialist so, I as I say, I go for understanding to supplement

ye in the diagrams you can see whats happening. If you just follow the formulas and you don't understand the topic very well you might use the wrong one.

Reply 13

TenOfThem

Original post by ChickenMadness

ye in the diagrams you can see whats happening. If you just follow the formulas and you don't understand the topic very well you might use the wrong one.

You may not have realised that I am not the OP

I am able to solve this problem - but thanks for your comments

Reply 14

Chicken.M.

Original post by TenOfThem

You may not have realised that I am not the OP

I am able to solve this problem - but thanks for your comments

lol well i was just saying as a general statement. since theres 3 people in here involved in that discussion.

Reply 15

thisworked

Original post by zed963

I pretty much hate this topic, I've no idea how to get over it.

I'm stuck on this question.

Hope this helps...

You're given the following probabilities:

P(E) = 2/5, P(B) 2/3 and P(R|B) = 9/25
(where E = those who exercise regularly and B = those who eat breakfast)
Using the formula for P(R|B), you can easily solve part (a) and hopefully the rest