AQA M1SB 8th of june 2016 unofficial markscheme

Yeah, that's exactly what I would've done. I must've made a mistake on something alone the way. Thank you for explaining!

Did you use the calculator or tables to find the probability?

By the way what was the assumption made, I said that the probability either side of the mean was 0.5 because even if something is normally distributed it sometimes isn't.

For question 7 wasn't the second claim valid since 20% had spent less than 200 euros and it said at most 25% spent 200 or less.

Tables I believe.

I got this as well

I worked out the probabilty of 1 bottle containing the amount required, which is 0.841, so the probability of all 6 is 0.841^6 = 0.354

it wasn't the first 10, as otherwise you would be comparing pounds to euros. You had to either convert the euros to pounds, or the pounds to euros and then find that it was 7/40 entries.

So did I, you may have just looked at the wrong value either side of the correct one in the table, which is a mistake I have made a few times before

is this for the in "each" part of the question

Yes

10% Contain more than 1535, so you're looking at the 90th percentile. Finding the Z value for this gives 1.28. You then sub this into the standardising formula to work out the new mean. The new mean ends up as being 1522.712. As it wants the difference, you do:

1525-1522.712
= 2.288
=2.3
i hope that's helpful g

10% Contain more than 1535, so you're looking at the 90th percentile. Finding the Z value for this gives 1.28. You then sub this into the standardising formula to work out the new mean. The new mean ends up as being 1522.712. As it wants the difference, you do:

1525-1522.712
= 2.288
=2.3
i hope that's helpful g

How many marks was this question?

I just worked out where I went wrong. I must've put 1.218 as my value for 90% rather than 1.28....

So annoying haha

Here's a few of my answers:

R=0.959
Mode = 26
IQR = 2

The 2 things were mean and SD

then Mean = 25.6
SD= 5.26

Equation of regression line was
y=181+3.00x
For the interpretation of gradient, i said that as the temperature increases by 1 degrees celcius, the mass of whatever dissolved etc increases by 3.00g
the estimation was 385g
i said large residuals so unreliable

then the probability questions i got
0.352
0.136
0.158
0.792
0.267
and the 5 marker probability i got 0.0205

The normal distrubuition ones i got
0.941
0.149
0.792
0.354
0.993

and the reduction in mean i got 2.3

The 4 marker binomial one i got 0.891

For the last question i disagree with first claim as after u make the new CI with the values in euros, 400 wasnt within the new CI, so claim was invalid.
The second claim which working out the eurors to pounds conversion gave 166.67, and it wanted less than that, i got 14% and i said that therefore claim is not true.
So first claim = invalid
Second claim= Invalid

and that's about it for all i remember/wrote down on extra paper i asked for.

What did u get for your confidence interval? everyone i got said the claim was valid but i said it was invalid :/

it wasn't the first 10, as otherwise you would be comparing pounds to euros. You had to either convert the euros to pounds, or the pounds to euros and then find that it was 7/40 entries.

Q3) probabilities - different ages and bands 1-3ai) 0.136ii) 0.158iv) 0.729v) I can't remember [9 marks for part a]b) 0.0308 [5 marks]

b) P(1515?<X<1540)

Q6) Normal distribution
volume of the bottles in a pack of 6
mean 508.5 , SD= 9.6?
ai) P(X>505) [NOT SURE IF THIS IS ACTUALLY ai)]