AQA AS Mathematics (Old Spec) - Statistics 1 MS1B - 06 June 2018 [Exam Discussion]

Did anyone fully understand the last question on conditional probability, something about P(U|T')=0.48 ? I got T' as 0.1152 but not convinced I did it right

Yeah. All you had to do the first one was do the probablility of all of them going which was 0.96x0.88x0.74 (I think those were the numbers) then times that by the probability of U going given that T goes (can’t remmeber value but it was the one on the left). I thought this probability question was a lot kinder than last years.

Reply 81

Jjohnson919

7

Original post by Jdot18

S11 =Approx 0.16
Sum all residuals = 0

That’s the one. Not 1.6😂 Because you got like -(whatever that number was can’t remember)+0.09 then add whatever to that to get 0?

Reply 82

Jjohnson919

7

Original post by MezmorisedPotato

Confidence interval values?

I think (1065,1085). No reason to doubt claim as 1072 millilitres lies within this range.

Reply 83

MezmorisedPotato

18

Original post by Jjohnson919

I think (1065,1085). No reason to doubt claim as 1072 millilitres lies within this range.

Yes got something like that 👍👍

Reply 84

dfhw

9

Anybody looking to get a MS on the go??

I got like 250 or something for n I think :frown:

Reply 85

£Tom

2

Original post by Jdot18

U did not effect T so p of T' was 1-p(T)

How did you work out P(T) when P(U|T)=0.96

Reply 86

Jjohnson919

7

Original post by £Tom

How did you work out P(T) when P(U|T)=0.96

Because the other probability was P(U/T’). Meaning that U goes given that T doesn’t go. The question asked the probability of all of them not going. So to find the probability of U NOT going given that T goes is 1-0.48=0.52.

Reply 87

rbunny98

7

wtf lol got w=6.06=6?

Reply 88

Jjohnson919

7

What did everyone answer for why a least squares regression line wasn’t suitable for x on y?
What did everyone answer on the second question where you had to estimate what the coefficients were (especially interested in B!). Cheers

Reply 89

elizabrown

5

do you think grade boundaries will be lower

Reply 90

Jdot18

4

Original post by Jjohnson919

What did everyone answer for why a least squares regression line wasn’t suitable for x on y?
What did everyone answer on the second question where you had to estimate what the coefficients were (especially interested in B!). Cheers

Y is response variable dependant on x,
-0.8
0 as its not linear

Reply 91

Jjohnson919

7

Original post by Jdot18

Y is response variable dependant on x,
-0.8
0 as its not linear

Get in. I basically said because if it was true it would mean that x was the response variable. Basically the same thing right?
And yeah I got exactly -0.8 and 0 too!

Reply 92

Jjohnson919

7

Original post by elizabrown

do you think grade boundaries will be lower

Ever so slightly. Maybe 59/60 for an A. Last year was big standard statistics. This year there were many things I think many people wouldn’t of got ie - sum of residuals = 0, N and W questions, binomial distribution conditions etc.

Reply 93

£Tom

2

Original post by Jjohnson919

What did everyone answer for why a least squares regression line wasn’t suitable for x on y?
What did everyone answer on the second question where you had to estimate what the coefficients were (especially interested in B!). Cheers

I said because it would give a perfect correlation (+1) which wouldn't be true but idk just a guess.
Other bit I put +0.7 and 0

Reply 94

Jdot18

4

Original post by Jjohnson919

Get in. I basically said because if it was true it would mean that x was the response variable. Basically the same thing right?
And yeah I got exactly -0.8 and 0 too!

Yea, what did you get for n and w?

Reply 95

Jjohnson919

7

Least squares regression line question.
The last part:
Extrapolation
For the numerical reason did you just put the numbers (150 and 200) into your regression line equation?
Wasn’t too sure on explaining why they weren’t suitable.

Reply 96

MajorFader

21

Who got 70 for N?

0.8851

One of my normal distribution answers I can remember

Reply 97

Jjohnson919

7

Original post by Jdot18

Yea, what did you get for n and w?

Didn’t get either lol. I came back to the N question at the end and got phi of Z and formed the equations but ran out of time. W question I found phi of Z and formed it in a normal distrubution. You think I’ll get 1 method mark for W question for finding phi of Z and 2 method marks for N question for finding phi of Z and forming equations with 1080 and 1060?