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Maths, Addmaths and Statistics: Post your doubts here!

A

aleezay

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Re: O'level Maths, Addmaths and Statistics help available he

doctormani said:
Statx ques :
7 (a) A school wished to estimate its examination costs per candidate for the coming year using the
previous year’s fees.
For each candidate there was a basic fee of $20 plus an additional fee of $30 for each subject
taken by that candidate. Using these figures, the school estimated that the cost per candidate
would have a mean of $230 and a standard deviation of $90.
However, before the entries were made, the fees had been increased to $25 per candidate
and $35 per subject.
Calculate the actual mean and standard deviation of the cost per candidate which the school
will have to pay for its examination entries in the coming year.
Click to expand...

i did it this way.......
let 230$ b d total fee of 1 student
so, 230 = 20 +30n
where n represents d no of subjects.by solving this equation we get n = 7

now, increase in fee = (25-20) + 7(35-30)
= 5 + 7(5) = 40

therefore, new mean = 230 + 40 = $270
since addition doesnt affect sd, rise in basic fee doesnt change d sd. however change in subject fee does cz u multiply d fee with d no. of subjects.
new sd = 90 x 35(7)/30(7)
solve n ul get $105
 
A

aleezay

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Re: Stats....Q....

usman.1995 said:
Pleazz tell anyone how 2 do this..???
Click to expand...

4 independent events, P(A and B) = P(A) x P (B)
suppose we select a woman out ov all the members of this club.if theri marital satus is independent of their age,then
P(woman selected is 25-29yrs old n divorced) should equal d product ov P(she belongs 2 ds age group) n P(she is divorced).
checking if that is the case...
11/92 ? 114/192 x 26/192 we get
0.057 is not equal to 0.080
therefore,d age groups ov women n their marital status rnt independent.
hope this helped =)
 
SalmanPakRocks

SalmanPakRocks

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Re: O'level Maths, Addmaths and Statistics help available he

aleezay said:
when locating d median 4 GROUPED data, is median (n/2)th term or (n+1/2)th term??
Click to expand...
when data is even (grouped)
(N/2)th value
the L+h/f(N/2-C.f)
when data is odd then
(N+1/2)thh value the same formula
 
J

Jai4ever

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Re: O'level Maths, Addmaths and Statistics help available he

FIRST find C.F
then if number of values are odd then FOR example 11+1/2
if numer of value are Even then 0.5(number of value /2 +(number of values+1/2
then use this formula Lower class limit of median + class width/frequency of medain class (total F/2 -C.F for preceding class from median class.............
 
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Jai4ever

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Re: O'level Maths, Addmaths and Statistics help available he

Can any give me suggestion how should i attempt comments Question ....i am weak in comments.........SO help Guys..........
 
J

Jai4ever

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Re: O'level Maths, Addmaths and Statistics help available he

aleezay said:
when locating d median 4 GROUPED data, is median (n/2)th term or (n+1/2)th term??
Click to expand...
FIRST find C.F
then if number of values are odd then FOR example 11+1/2
if numer of value are Even then 0.5(number of value /2 +(number of values+1/2
then use this formula Lower class limit of median + class width/frequency of medain class (total F/2 -C.F for preceding class from median class.............
 
A

aleezay

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Re: O'level Maths, Addmaths and Statistics help available he

i ddnt get the part whr u explained d procedure 4 an even no ov observations..
 
J

Jai4ever

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Re: O'level Maths, Addmaths and Statistics help available he

aleezay said:
i ddnt get the part whr u explained d procedure 4 an even no ov observations..
Click to expand...
K i am giving u example for
TOtal frequency is 100
0.5(100/2 +100+1/2)
whaterever the answer comes see in which class it lays .......then use median for group data formula
 
J

Jai4ever

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Re: O'level Maths, Addmaths and Statistics help available he

Can any give me suggestion how should i attempt comments Question ....i am weak in comments.........SO help Guys..........
??????????
 
S

sohaibh7

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Re: O'level Maths, Addmaths and Statistics help available he

plz tell me how to finnd height in histogram urgent................ sampling qs p1
 
H

hassankhan

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Re: O'level Maths, Addmaths and Statistics help available he

Can anyone tell me how we find the height in histogram and plz solve stats 2010 p1 Q6 session 11... Urgent
 
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Jai4ever

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Re: O'level Maths, Addmaths and Statistics help available he

hassankhan said:
Can anyone tell me how we find the height in histogram and plz solve stats 2010 p1 Q6 session 11... Urgent
Click to expand...
frequency/classwidth*factor=height for histrogram
 
W

waztaz123

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W

waztaz123

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Re: O'level Maths, Addmaths and Statistics help available he

Jai4ever said:
http://www.xtremepapers.com/CIE/Cambridge%20O%20Levels/4040%20-%20Statistics/4040_w10_qp_21.pdf
Help me in Q7
Click to expand...

(i)(a) ((109+107+113+110+106)/500)*100
=(545/500) *100= 109

(b) It does not take weights into account

(ii) Just multiply the December price relatives with their weights. Divide the answer by (100*20) and u will get 109.25 rounded to 109. (In January every price relative will be 100)

(iii) (113/109)*100= 103.6 rounded to 104

(iv) C as it directly affects their cost of living.

(v)(a) The answer to (ii) was calculated with January1st as Base. This value was calculated with June30th as base and price had increased since then.

(b) The base date and the date on which the weights had been calculated were different and that therefore these weights may not have remained accurate for the new base date.
 
T

tahatehseen

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Re: O'level Maths, Addmaths and Statistics help available he

many times there is a question related to index in the paper which says: How could have the weights been calculated? does anyone know the answer?
 
A

aleezay

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Re: O'level Maths, Addmaths and Statistics help available he

waztaz123 said:
Can anyone tell me what is the difference between paper 21 and paper 23? Both are Statistics paper 2 of 2010....have the CIE started to give different papers?
Don't tell me that I didn't knew of it 1 day before the exam!

http://www.xtremepapers.com/CIE/ind...ls/4040 - Statistics/&file=4040_w10_qp_21.pdf
http://www.xtremepapers.com/CIE/ind...ls/4040 - Statistics/&file=4040_w10_qp_23.pdf
Click to expand...
same is d case here!lol!
 
A

aleezay

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Re: O'level Maths, Addmaths and Statistics help available he

tahatehseen said:
many times there is a question related to index in the paper which says: How could have the weights been calculated? does anyone know the answer?
Click to expand...
by figuring out d imp ov each item....either by calculatng d amount spent on each item or by d quantity ov each item

ALL THE BEST EVRYBDY! WISH ME LUCK!
 
H

hassankhan

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Re: O'level Maths, Addmaths and Statistics help available he

Can anyone help me wid Q 4 p2 2010 session 21....its urgent
 
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