AQA Statistics

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Reply 40

anon123

mean i got 180.5
s.d i got sumthin like 5. sumthin

ive no idea if im right!

Reply 41

Gothic pixie

lucasharrison

390 good at spanish
p(good at spanish)=0.78
that means 500 people alltogether ( 390/0.78=500)
p(french)=0.8
0.8x500=400

Very clever! Probably didn't help that i read the question wrong tho! nevermind, not worth worrying about- no more stats ever! yay! :smile:

Reply 42

IZZY!

**** there goes another 3 marks. or how many marks was that.

Reply 43

Gothic pixie

Yeah- 3 marks, but u can't have done that badly...most of my friends came to virtually no lessons, did almost no revision, and will hopefully bring the boundaries down! Damn those year 10s tho- they're gonna do way better cos they only had one sodding exam to revise for :mad:

Reply 44

IZZY!

what did u get for question when u had to calculae the weighted mean for histograms. i dont rly remember what was that.

Reply 45

Gothic pixie

IZZY!

what did u get for question when u had to calculae the weighted mean for histograms. i dont rly remember what was that.

I don't remember that one- i thought it was the median that u had to estimate.....or was there another question too?

Reply 46

Davror

it was the median, how did u do it?

Reply 47

IZZY!

oh yer median
well i found the total cumulative frequency on the table. it was something like 120+1/2=60.5 th value. then find the cululative frequency which includes the 60.5th value on the table. then find the mid interval value of the class width the median lies in.is it right?

Reply 48

IZZY!

i beg god to make grade boundaries lower this year. please god plzzz plzzzz i beg u.

Reply 49

Mark S

IZZY!

My mathematician friend says 'yes probably' izzie :biggrin:

Reply 50

IZZY!

lol, who is maths friend?

Reply 51

Gothic pixie

Please, please, please tell me that the total cum freq was 125 not 120- i was looking for the 63rd value on the basis that median = n+1 / 2 and i read it as 125. sod it!

Reply 52

Mark S

IZZY!

lol, who is maths friend?

lol hes not a member of TSR but hes ive just spoken to him, he gets A*s in maths and stats etc etc, he says your probably right which is good :smile:

Reply 53

IZZY!

Gothic pixie

Please, please, please tell me that the total cum freq was 125 not 120- i was looking for the 63rd value on the basis that median = n+1 / 2 and i read it as 125. sod it!

i think it doesnt matter, because 63rd and 60.5 th values are included in the same class width so u should have got the right median in the end.

Reply 54

IZZY!

Markus505

lol hes not a member of TSR but hes ive just spoken to him, he gets A*s in maths and stats etc etc, he says your probably right which is good :smile:

lol thats goood. ask him about the last question.lol

Reply 55

Davror

What did you get for an answer?

Reply 56

Mark S

IZZY!

lol thats goood. ask him about the last question.lol

I have, he said he didnt know because even he fonud it quite hard, i asked him whether it was 108.33333 and he said maybe but he says he thought it might be higher than that...anything you want asked just pass it on..

Reply 57

IZZY!

i didnt use calculations. I said that the maximum value for the mean with s.d. of 10, meaning with distribution of 100 is 150, because half of 100 goes on one side and half on other. I just imagines the distribution graph.lol. So in the end the volume should have been more than 150ml.lol. I am not rly sure.