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# Statistics Question watch

1. a fair coin is tosses repeatedly untill a head appears or 3 tosses have been made. The random variable T represents the number of tosses.

A) show that P(T=2) = 1/4

i have no idea how to answer this question i am absolutely confused. Any help would be apreciated thank you.
2. (Original post by sonic23)
a fair coin is tosses repeatedly untill a head appears or 3 tosses have been made. The random variable T represents the number of tosses.

A) show that P(T=2) = 1/4

i have no idea how to answer this question i am absolutely confused. Any help would be apreciated thank you.
A head appearing has a probability of 1/2
Therefore, if T = 2, it has been rolled twice.

Therefore, the probability a head will show after two tosses is 1/2 x 1/2 = 1/4

I think that's right anyway.. Was never that good at stats but got an A
3. Thank you would tht be sufficient?
4. (Original post by Danielisew)
A head appearing has a probability of 1/2
Therefore, if T = 2, it has been rolled twice.

Therefore, the probability a head will show after two tosses is 1/2 x 1/2 = 1/4

I think that's right anyway.. Was never that good at stats but got an A
I don't think this is right..
5. what ive written is :

the only way in which 2 tosses can be made is if the first toss is not a head and the second toss is a head which is :

1/2 x 1/2 = 1/4

is tht ryt?
6. (Original post by sonic23)
what ive written is :

the only way in which 2 tosses can be made is if the first toss is not a head and the second toss is a head which is :

1/2 x 1/2 = 1/4

is tht ryt?
7. damn ryt
8. I found probability the hardest topic in S1, so don't worry because it can only get easier.. never understood probability apart from Venn diagrams really.

In the real test, I got most of the probability right but lost 4 marks from it and then another 7/8 marks elsewhere, which gave me 85/100 - exactly what I predicted.

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