- #1
Mo
- 81
- 0
I absolutely hate stats! its got to be one of the worst topics going.Anyway here is the (simple) question i am having (lots) of problems with! (im revising over and can't remember a thing!)
"In each of the following questions, list a sample space consisting of equally likely outcomes and hence find the required probabilities"
1) There are 5 counters in a bag, each marked with a different number from the set {1,2,3,4,5} .Two counters are drawn from the bag,Find the probabaility the total score on the counters is
a) greater than 7
b) a prime number*
c) an odd number*
I made up a sample space diagram and i find out that out of 20 possible outcomes, 4 added up to be greater than 7. So my answer was 1/5
However i reread it and i done it through another way ... i said:
p(grater than 7) is the probabaility we get... p(3,5) + p(5,3) + p(4,5) + p(5,4)
(ok so this is essentially the same) BUT the probability of getting a 3 is 1/5 right? so we get (1/5 X 1/5) X 4 = 4/25
so ... which one i correct?
Please, please help!
Regrads
Mo
* i think ill attempt these again once i know the answer for this.
"In each of the following questions, list a sample space consisting of equally likely outcomes and hence find the required probabilities"
1) There are 5 counters in a bag, each marked with a different number from the set {1,2,3,4,5} .Two counters are drawn from the bag,Find the probabaility the total score on the counters is
a) greater than 7
b) a prime number*
c) an odd number*
I made up a sample space diagram and i find out that out of 20 possible outcomes, 4 added up to be greater than 7. So my answer was 1/5
However i reread it and i done it through another way ... i said:
p(grater than 7) is the probabaility we get... p(3,5) + p(5,3) + p(4,5) + p(5,4)
(ok so this is essentially the same) BUT the probability of getting a 3 is 1/5 right? so we get (1/5 X 1/5) X 4 = 4/25
so ... which one i correct?
Please, please help!
Regrads
Mo
* i think ill attempt these again once i know the answer for this.