[kj14]

(Original post by mrxstardust)
Yh the denominator was 194, because the selection was out of the 3 bedroom houses only. I got 0.095 for that i think.

Wow got the same answer as you man WOOHOO gonna ace this unless the stupid grade boundaries bring me down!

[mrxstardust]

(Original post by kj14)
Wow got the same answer as you man WOOHOO gonna ace this unless the stupid grade boundaries bring me down!

yh dude apart from the previous wording on the probability ones, and some comment questions im unsure about. I think i got my marks back from that wreck of a c2 paper.

[Implo]

(Original post by warg85zak)
i finished with 40 minutes to spare...

Wtf! I found it easy as hell but ran out of time So depressing!

[uxa595]

(Original post by kj14)
Wow got the same answer as you man WOOHOO gonna ace this unless the stupid grade boundaries bring me down!

Yh, if it was 2 marks i reckon ive got 1 for the calc of the 3 seperate probabilities whih i should have eventually multiples together.

What do you all the think the B boundaries are?
My other exams have buffered me up nicely so i dont even have to do c4 as long as i get 71

Still a facepalm moment when i sat there for 5 min and couldnt do the norm dist question when inhad just just z=x-u/SD just a sec ago.

I reckon at most i lost the 6+2+5 marks for silly mistakes on the worded questions.
Should hopefully get over 60/75

[mrxstardust]

(Original post by uxa595)
Yh, if it was 2 marks i reckon ive got 1 for the calc of the 3 seperate probabilities whih i should have eventually multiples together.

What do you all the think the B boundaries are?
My other exams have buffered me up nicely so i dont even have to do c4 as long as i get 71

Still a facepalm moment when i sat there for 5 min and couldnt do the norm dist question when inhad just just z=x-u/SD just a sec ago.

I reckon at most i lost the 6+2+5 marks for silly mistakes on the worded questions.
Should hopefully get over 60/75

An A was 56 in jan and was 59 in june 11, so you may be lucky and get an A

[mrxstardust]

(Original post by uxa595)
Yh, if it was 2 marks i reckon ive got 1 for the calc of the 3 seperate probabilities whih i should have eventually multiples together.

What do you all the think the B boundaries are?
My other exams have buffered me up nicely so i dont even have to do c4 as long as i get 71

Still a facepalm moment when i sat there for 5 min and couldnt do the norm dist question when inhad just just z=x-u/SD just a sec ago.

I reckon at most i lost the 6+2+5 marks for silly mistakes on the worded questions.
Should hopefully get over 60/75

It was a 4 mark question, 1 mark for correct data, 1 mark taking 1 away from the denominator, 1 mark for multiplying the probabilities and and last mark for correct answer.

[uxa595]

(Original post by mrxstardust)
It was a 4 mark question, 1 mark for correct data, 1 mark taking 1 away from the denominator, 1 mark for multiplying the probabilities and and last mark for correct answer.

In that case i got 0
Still i reckon low 60's High 50's Which is enough for me

[Georgehalford1994]

anyone fancy doing a markscheme? or posting the exam pages on here.

[AvaSofia]

(Original post by Butdidudie)
I added up all the original letters from royal mail, then added the 280 then divided by the amount of days 175 and got 23.9. but I'm not sure. It could of been everything really.

I did that as well

[JulietheCat]

Well, the mistakes I made were:

-The two regression lines didn't intersect when I drew them but actually they do.

-I was not too sure about the two claims explanation questions.

I need to get a B or higher. I've been doing both past papers and Solomon papers for practice...

[Alex0619]

(Original post by speed2001)
For the last probability question, wouldn't the denominator be 194 (or something like that) because it said that they picked from only the 3 bedroom houses.

So wouldn't it be probability of having either 2,3, 4 or more toilets GIVEN that its a 3 bedroom house

yeah

[Georgehalford1994]

for the probability you had to do the given number / 194 then 193 and 192 as you were choosing without replacement. has anyone got a markscheme?

[thedifferentiator]

(Original post by Butdidudie)
I added up all the original letters from royal mail, then added the 280 then divided by the amount of days 175 and got 23.9. but I'm not sure. It could of been everything really.

Didnt have to do that. Just work out the mean of the new letters 280/175 and add it to the old mean.

Think about it, if you had 12 letters over 3 days the mean would be 4. If they asked you to find the new mean if 3 new letters came from external sources then 3/3 the mean would be 1 a day. Add the two means together =5 as it does if you added all the letters together to get 15 and divided by 3. Thats how I done it, instead of wasting my time adding up all the god damn letters

Overall the exam went well for me I think.

[Failure360]

I got (4. something, 5. something) for the confidence interval one?????

[mrxstardust]

(Original post by Failure360)
I got (4. something, 5. something) for the confidence interval one?????

sorry to say but that is wrong, the CI should be above 5, maybe its because you used the 75 as the standard dev, most people made this error, you had to convert the millilitres into litres, so divide by a 1000. Standard deviation is affected by multiplication and division so your sd must be 0.075/Root(n).

[Failure360]

(Original post by mrxstardust)
sorry to say but that is wrong, the CI should be above 5, maybe its because you used the 75 as the standard dev, most people made this error, you had to convert the millilitres into litres, so divide by a 1000. Standard deviation is affected by multiplication and division so your sd must be 0.075/Root(n).

OH I'm such an idiot I did 0.75 not 0.075. Great that's what 11 marks down the drain.

[mrxstardust]

(Original post by thedifferenatiator)
Didnt have to do that. Just work out the mean of the new letters 280/175 and add it to the old mean.

Think about it, if you had 12 letters over 3 days the mean would be 4. If they asked you to find the new mean if 3 new letters came from external sources then 3/3 the mean would be 1 a day. Add the two means together =5 as it does if you added all the letters together to get 15 and divided by 3. Thats how I done it, instead of wasting my time adding up all the god damn letters

Overall the exam went well for me I think.

if you worked out the sd in the previous question this method would be easier, because sigma FX is the amount of letters so add 280 to that and divide by 175.

[mrxstardust]

(Original post by Failure360)
OH I'm such an idiot I did 0.75 not 0.075. Great that's what 11 marks down the drain.

dont be too hasty, method marks are 4, and you only get 1 mark for the correct answer. 1 mark for getting the correct z value. 1 mark for using the correct formula, and another for using the correct sd, and last mark for the answer, you could pick up two marks.

[Rainingshame]

(Original post by KTucker93)
yeh think the grade boundaries are going to be so high! answered everything, but ran out of time and missed out two 2 mark Q's that will probably be a whole grade! also think when I did 1- on one of the Q's it was wrong. oh well, they can't make the boundaries tooo high!

Me too, i hope not THAT high, i made a silly mistake on the second last question....

[Sophocrates]

(Original post by mrxstardust)
dont be too hasty, method marks are 4, and you only get 1 mark for the correct answer. 1 mark for getting the correct z value. 1 mark for using the correct formula, and another for using the correct sd, and last mark for the answer, you could pick up two marks.

Agreed, most of the time in mark schemes, if you have made one error and it's systematic and so continues on to your other answers, you still get marks for using your b)i) or ii) answer, for example. It is stated in many past paper mark schemes.
Don't worry! Not all 11 marks are lost.