The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

Edexcel S1 - 15th June, 2016 [Exam Discussion]

Scroll to see replies

Reply 780
Avatar for candol
candol
7
Original post by Adorable98
How do I work out the percentages of a box & whisker plot!! :frown:


Also, worth remembering that on the box plot the only points you know for certain are outliers/or max/min the quartiles (and median)
Reply 781
Avatar for candol
candol
7
Original post by Kadak
Formula for skewness of quartiles ?


also, don't forget if you get asked on skewness, see what they were asking you to find earlier in the question, as this will give you a big clue as to which measure you should use (eg mean vs median, or quartiles or shape of box plot or formula)
Reply 782
Avatar for Egge
Egge
1
Is (AuB)' the same thing as (AnB)' as shown in this video? https://www.youtube.com/watch?v=b6t0994ZZDA Thanks in advance and good luck everyone!
Original post by kosvengali
Posted from TSR Mobile

How does coding work with the mean, variance and standard deviation?


For mean it usually works by just substituting the value into x and you work it out normally. However, for standard deviation, when doing a code that is for example (x-100)/5, you ignore the -100 as it is not affected (I forgot why but I'm pretty sure that's what you do) - so you do (standard deviation)/5. For variance, I'm not sure they'll ask us to code the variance but I think it's a similar concept to standard deviation, unless you're talking about Var(X) or something like that.
For your answers do you guys give them to 3sf or 2 dp or how do you answer the questions, because i uasually get long answers!
Original post by kosvengali
Posted from TSR Mobile

How does coding work with the mean, variance and standard deviation?


Coding does not affect product moment correlation coefficient
Mean {E (X )} is affexted by + × ÷ -
Variance { (Var (X) } is affexted by only ÷ ×
Original post by Egge
Is (AuB)' the same thing as (AnB)' as shown in this video? https://www.youtube.com/watch?v=b6t0994ZZDA Thanks in advance and good luck everyone!


Yeah I guess so but you would usually write (AuB)' = A'nB'
What definitions do we have to know?
E.g sample space
Normal distribution prabability
Original post by govandpolitics
dya reckon it will be an easy or a hard paper?


harder than diamond
What are the advantagesand disadvantages of a statistical model
Reply 790
Avatar for Egge
Egge
1
Original post by Jozanic
Yeah I guess so but you would usually write (AuB)' = A'nB'


Okay thanks for the quick reply! Good luck :smile:
Reply 791
Avatar for candol
candol
7
Original post by Egge
Is (AuB)' the same thing as (AnB)' as shown in this video? https://www.youtube.com/watch?v=b6t0994ZZDA Thanks in advance and good luck everyone!


NO!!. Your (A intersect B)' is not what he is drawing.
He is drawing A' intersect B' these are different
Please be careful
If in doubt in the exam, translate the maths notation to what it reads in regular english
Original post by remylawson
What are the advantagesand disadvantages of a statistical model


Advantages: predictions can be made, quick +easy, simplifies a complex situation.

Disadvantages: partial description of real situation, only works for restricted range of values


Posted from TSR Mobile
Just mangers to cram s1 all of last ought and manger to get 60/75 on Jan ial just hoping the paper today is like that


Posted from TSR Mobile
Reply 794
Avatar for Egge
Egge
1
Original post by candol
NO!!. Your (A intersect B)' is not what he is drawing.
He is drawing A' intersect B' these are different
Please be careful
If in doubt in the exam, translate the maths notation to what it reads in regular english


Oh god, I'm starting to get confused - I always thought (Anb)' was the same thing as A' intersect B'.
What would (AnB)' be then??
Reply 795
Avatar for candol
candol
7
Original post by Egge
Oh god, I'm starting to get confused - I always thought (Anb)' was the same thing as A' intersect B'.
What would (AnB)' be then??


well A intersect B is just the bit where the 2 overlap.
If you then 'Not' it you are left with everything else
Original post by candol
NO!!. Your (A intersect B)' is not what he is drawing.
He is drawing A' intersect B' these are different
Please be careful
If in doubt in the exam, translate the maths notation to what it reads in regular english


He was drawing (A union B)'
So it's right.
Also for (A intersection B)' do you colour in everything except for the intersection (so is A and B also coloured)?
For b of this question, what does the question mean? What is it asking us to do?
I've looked at the markscheme and exam solutions but I still don't understand.
Reply 798
Avatar for candol
candol
7
Original post by asinghj
He was drawing (A union B)'
So it's right.
Also for (A intersection B)' do you colour in everything except for the intersection (so is A and B also coloured)?


I didn't say he wasn't right. What you wrote in your post was not what he was drawing in the intersection part of the video. That's why I said be careful
Quick last minute stress question..
Say e(x) = 3 and var(x)=2

Find e(2x^2+3x)


Would this be
var(x) = E(x^2)-E(X)^2
Therefore E(x^2) is 11
making e(2(11)+3(3))
Resulting in the final answer being
31

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you