A level Statistics doubt??Post your doubts here!

[syed1995]

ok but i dint get the part "Since loss means a profit that is less than zero, we are working P(X<0)"

Profit means .. Total Sales are greater than Total Cost... Sale Price - Cost Price like if you sell a book which you bought for 10$ (cost) for 15$ (sale) you get a profit of 5$..

similarly if you sold the same 10$ item (cost) for 8$ (sale) you have a 2$ loss .. Now use the profit formula .. Sales - Cost = 8-10= -2 .. meaning Negative Profit is loss.. hence less than 0.

 

[sma786]

Kangxidi ,

actually the no mentioned is the profit so u cannot be in loss

Thanks both of you Got it now !

 

[Alice123]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s12_qp_61.pdf
no 5iii how do we find the sd... im sure we dnt hav to work half a page for a 1 mark qs

 

[syed1995]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s12_qp_61.pdf
no 5iii how do we find the sd... im sure we dnt hav to work half a page for a 1 mark qs

Poor marking done by CIE here.. no way other than underroot of " (Sum of x^2)/n - mean^2"

 

[sufyanalizaib]

aoa people plzzz help me out wid this shitty questio.... question 5 part 1

 

[immie.rose]

Some really gud note available on Statistics here:
http://people.richland.edu/james/lecture/m170/

JazakAllah...these notes are really useful.
I hv a doubt though...Under the "guidelines for classes "(i.e. class widths) ...it says

1. The classes must be equal in width. The exception here is the first or last class. It is possible to have an "below ..." or "... and above" class. This is often used with ages.

I don't quite get this...how could i compute class widths of say, histograms or CF, if the question involves ages?

 

[syed1995]

aoa people plzzz help me out wid this shitty questio.... question 5 part 1

Here's the working... You will understand it now..

P(20-12<X<20+12)=0.94
P(8<X<32)=0.94
P(8-20/SD<z<32-20/SD)=0.94
P(-12/SD<z<12/SD)=0.94
2Phi(12/SD)-1=0.94
2Phi(12/SD)=1.94
Phi(12/SD)=0.97
12/SD=inversePhi(0.97)

And use the table to solve it.

 

[syed1995]

aoa people plzzz help me out wid this shitty questio.... question 5 part 1

Just tag me in any of your questions and I will help ya.. just type "@ syed1995" And I will respond for sure

 

[SexyFag]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s12_qp_62.pdf


syed1995
Question 2 both parts?

 

[sufyanalizaib]

thanx broo...hres another question question 6 part 2

 

[sufyanalizaib]

thanx broo...hres another question question 6 part 2

 

[Soldier313]

Aoa wr wb
Cam someone please help me with qn 3 of this paper, when we have to draw the histogram, how do we know the width of the bars, i mean i drew it with the bars going from like 0-10, 10-15, but then realised the ms had drawn the something quite different!
http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w12_qp_62.pdf
http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w12_ms_62.pdf

syed1995 and everyone else
JazakAllah khair!

 

[syed1995]

Aoa wr wb
Cam someone please help me with qn 3 of this paper, when we have to draw the histogram, how do we know the width of the bars, i mean i drew it with the bars going from like 0-10, 10-15, but then realised the ms had drawn the something quite different!
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w12_qp_62.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w12_ms_62.pdf

syed1995 and everyone else
JazakAllah khair!

Class widths are not same in all the intervals.. so you will have to find frequency density.. it is frequency/class width.. so for 0<t<10 .. it will be 19/10 .. for 10<t<15 .. it will be 12/5 .. and so on.. then draw the graph with Frequency density on Y axis instead of frequency.

Cheers

 

[Soldier313]

Class widths are not same in all the intervals.. so you will have to find frequency density.. it is frequency/class width.. so for 0<t<10 .. it will be 19/10 .. for 10<t<15 .. it will be 12/5 .. and so on.. then draw the graph with Frequency density on Y axis instead of frequency.

Cheers

yes bro i did that, but the pro is these widths of the bars, mine run from 0-10, 10-15, but look at the ms, they have drawn the width to be 0-15, 15-25 etc which is what i don't get :/

 

[syed1995]

yes bro i did that, but the pro is these widths of the bars, mine run from 0-10, 10-15, but look at the ms, they have drawn the width to be 0-15, 15-25 etc which is what i don't get :/

A mistake in the MS Drawing.. just check at the top.. the FD is same... check where those intervals are coming.. they are wrong.. one can't interval at those values!

 

[sufyanalizaib]

Class widths are not same in all the intervals.. so you will have to find frequency density.. it is frequency/class width.. so for 0<t<10 .. it will be 19/10 .. for 10<t<15 .. it will be 12/5 .. and so on.. then draw the graph with Frequency density on Y axis instead of frequency.

Cheers

SYED BROO GIVE MY ANSWER PLZZZZZZZ

 

[Soldier313]

A mistake in the MS Drawing.. just check at the top.. the FD is same... check where those intervals are coming.. they are wrong.. one can't interval at those values!

oww cool thanx! I hate it when the ms is wrong! wastes sooo much of my time!!!

 

[syed1995]

oww cool thanx! I hate it when the ms is wrong! wastes sooo much of my time!!!

Haha never doubt yourself

 

[Rabb94]

hi
could someone solve ques 5i
http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w11_qp_61.pdf

 

[Soldier313]

hi
could someone solve ques 5i
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w11_qp_61.pdf

i believe it's just been answered here:
https://www.xtremepapers.com/community/threads/mathematics-post-your-doubts-here.9599/page-482