AQA Maths S2 18/06/10 PM

piccolo12345

question with the number of engineers at 11am, i couldnt even understand that too confusing put sommat random like 0.007 or something. and the discrete probability questions which proves something equals 0.24, lol neva seem a question like that in a past paper... what did everyone do for that? I basically put any value in the calculator and I found out that if you multiply the 2 variances together then divide by 8, it equals 0.24 lol.. doubt thats right tho :s-smilie:

You just had to find all the probabilities of R+S=6,7,8 by multiplying from both the tables, then add them all up and you got 0.24.

Reply 61

Zeento

OP

2

DannyH

rejected both too, checked them aswell

one had yates other was just standard right

Were we wrong? :frown:

Reply 62

piccolo12345

Adam92

You just had to find all the probabilities of R+S=6,7,8 by multiplying from both the tables, then add them all up and you got 0.24.

why just 6, 7 and 8? i thought the question was P<8 so wouldnt that include all values like 1,2,3 etc ?

Reply 63

Adam92

13

piccolo12345

why just 6, 7 and 8? i thought the question was P<8 so wouldnt that include all values like 1,2,3 etc ?

Yeah but the probability of 2 or lower was 0, so you couldn't make 5, because you would need 2 for the first, then 3, which can't be done. Hence the minimum is 3 from both.

Reply 64

moocow123

I said the woman was right, the mean had increased from 79. reject ho
On chi squared question i said there was no association between drugs and sickness. accept ho.

Was there another H0/H1 question?

On the "show its 0.24" question i did...
P(R=4)*P(S</=4) + P(R=5)*P(S<=3) + P(R=3)*P(S</=5)
and it came to 0.24

For the P(R=4) given that P(R+S</=8 ) question i got 0.11/0.24.

Oh and on the engineer question... I used Po(0.875) i think and said probability they cannot be seen at 11am was = 1-P(4 or less)

Anyone get these answers?

Reply 65

DannyH

1

moocow123

I said the woman was right, the mean had increased from 79. reject ho
On chi squared question i said there was no association between drugs and sickness. accept ho.

Was there another H0/H1 question?

On the "show its 0.24" question i did...
P(R=4)*P(S</=4) + P(R=5)*P(S<=3) + P(R=3)*P(S</=5)
and it came to 0.24

For the P(R=4) given that P(R+S</=8 ) question i got 0.11/0.24.

Oh and on the engineer question... I used Po(0.875) i think and said probability they cannot be seen at 11am was = 1-P(4 or less)

Anyone get these answers?

did you use yates correction on the chi squared?

Reply 66

Adam92

13

moocow123

I said the woman was right, the mean had increased from 79. reject ho
On chi squared question i said there was no association between drugs and sickness. accept ho.

Was there another H0/H1 question?

On the "show its 0.24" question i did...
P(R=4)*P(S</=4) + P(R=5)*P(S<=3) + P(R=3)*P(S</=5)
and it came to 0.24

For the P(R=4) given that P(R+S</=8 ) question i got 0.11/0.24.

Oh and on the engineer question... I used Po(0.875) i think and said probability they cannot be seen at 11am was = 1-P(4 or less)

Anyone get these answers?

Yeah the same, except the conditional probability one. How'd you go about working that one out?

Reply 67

Weeman5872

For the first hypothesis question [H0:], I used t. And rejected the null hypothesis.

For the chi question, I used Yate's correction, and accepted H0.

For the rectangular distribution [I think], I got median = 1 and q1 = 0.5