Maths, Addmaths and Statistics: Post your doubts here!

[SalmanPakRocks]

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

I solved the question again ! The mean is basically 246.04 not 246.64 !! The answer comes right if you use 04 !! Do it again now !!

Oops! I had done this in a bad hand writing and this resulted in me taking it as 64 !!
Sorry !!

 

[VelaneDeBeaute]

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

Hota hai ! But u cant afford such things in exams, can you ! :no:

 

[SalmanPakRocks]

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

Hota hai ! But u cant afford such things in exams, can you ! :no:

yeah totally, I got to clean up my hand writing and to do calculations without haste

 

[muzirox]

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

What does this means ? Source N08/P1/Q7
Using a scale of 2 cm to represent 10 kg, starting at −10 kg, on the horizontal axis, and a
scale of 2 cm to represent 2 people per 5 kg on the vertical axis, draw on graph paper a
histogram to illustrate these data.
Should we use Frequency Density in the vertical axis or not ? I m confused here.

No we have to calculate hight of rectangle by taking 5 as standard,the scale means 1cm to represent 1 people per 2.5 kg
I think this shud b done if i'm wrong plzz correct me

 

[waztaz123]

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

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.

This is not a scaling question. Knowledge of how the standard deviation and the mean is affected by addition,subtraction, multiplication and division is more required here.

Equation of previous years cost will be:

20+30x=230 (where x is the average number of subjects given by students)
30x=210 and so x=7

Since the school is only estimating next year's cost, we well assume that x(subjects given by students) remains unchanged.

Mean of next year= 25+35(x)= $270, therefore $270 is the mean for the coming year.

Now comes the hard part that is of the standard deviation. We cannot calculate standard deviation using the equation like we did for mean. But we know one important fact about the standard deviation i.e (it remains unchanged by addition or subtraction and is affected by multiplication, division by the same factor). Using this, we would know that only the change in fee per subject would count, as that is being multiplied.

Last year fee per subject= $30
Next year fee per subject= $35

New s.t.d: Old s.t.d= 35:30

New s.t.d= 90*(35/30)= 105

 

[Jai4ever]

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

Can any one provide me link for reading the for statictics exam tips posted by the Admins.?????????????

 

[falcon678]

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

hey for add maths is there only this book by Soo Thong Ho, Nyak Hiong Khor

is there any other book as well

a very imp question....

 

[waztaz123]

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

HEY I NEED HELP WITH STATS
N01/P1/Q8

I have problem finding out the verticle height of Histogram and also with finding the standared deviation.
In standard deviation I tried everything but when I put the formula it gives me Math Error!
Can some please urgently help me in here?

Yeah this histogram is a bit confusing and if you check the examiner report it says that very few candidates got the histogram right.

Also I'm not sure if I'm correct but I'll give it a try.

Well the class interval of 2.04< d <2.05= 0.01

Therefore the question says that 18 cm are to represent 36 bolts with class interval of 0.01. This is equal to 0.5 cm to represent 1 bolt with class interval of 0.01. Which is equal to 1 cm to represent 1 bolt with class interval of 0.005.[/b]

In other words, Frequency density in this question is 0.005mm per 1 bolt.

The classes with class interval of 0.01, their frequencies are to be halved.
The classes with class interval of 0.02, their frequencies are to be divided by 4.
The classes with class interval of 0.03, their frequencies are to be divided by 6.

So the first class will be divided by 3

24/3=7
36/2=18 (same height as given in the question)
26/2=13
22/2=11
12/2=6

You don't have to use such a long procedure, its just more or less common sense. I did it for explanation.

 

[SalmanPakRocks]

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

HEY I NEED HELP WITH STATS
N01/P1/Q8

I have problem finding out the verticle height of Histogram and also with finding the standared deviation.
In standard deviation I tried everything but when I put the formula it gives me Math Error!
Can some please urgently help me in here?

Yeah this histogram is a bit confusing and if you check the examiner report it says that very few candidates got the histogram right.

Also I'm not sure if I'm correct but I'll give it a try.

Well the class interval of 2.04< d <2.05= 0.01

Therefore the question says that 18 cm are to represent 36 bolts with class interval of 0.01. This is equal to 0.5 cm to represent 1 bolt with class interval of 0.01. Which is equal to 1 cm to represent 1 bolt with class interval of 0.005.

In other words, Frequency density in this question is 0.005mm per 1 bolt.

The classes with class interval of 0.01, their frequencies are to be halved.
The classes with class interval of 0.02, their frequencies are to be divided by 4.
The classes with class interval of 0.03, their frequencies are to be divided by 6.

So the first class will be divided by 3

24/3=7
36/2=18 (same height as given in the question)
26/2=13
22/2=11
12/2=6

You don't have to use such a long procedure, its just more or less common sense. I did it for explanation.

I got that Histogram thing
See do what ever you do to find Frequency density, (f.d = f/c.w) after you have found that make sure you read the question and understand what they say and for which class boundary they have given the height.
let say for e.g: height is 1 as stated by the question.
so we some how have to make that class equals to that height.
let say we have f.d
0.2 x 5= 1 !!

 

[Jai4ever]

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

Can any one provide me link for reading the for statictics exam tips posted by the Admins.?????????????????????????????
reply soon WHO KNOWS THAT........

 

[hassankhan]

STATS HELP PLZZZZZZZZZ

Can anyone tell me how many questions choice we have in stats paper as i m very confused.... Help will be highly appreciated

 

[muzirox]

Re: STATS HELP PLZZZZZZZZZ

Can anyone tell me how many questions choice we have in stats paper as i m very confused.... Help will be highly appreciated

In both papers;p1 & p2 have the total of 11 qs. in section A 6 qs which 've which all have to b attempted means no choice in section A.
Section B comprises of 4 qs (7 to 11)in which candidates r expected to do any three out of 4 qs means choice one qs in sec. B,same for both papers
Hope it really helps u,u can see the instructions given at the start of every paper

 

[Alchemist4lyf]

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

Correction = In section B, you do any 4 out of the 5 questions (7,8,9,10,11).

 

[Jai4ever]

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

Any one therE???
Tips to solve paper for statistics??????????????????????????????????????//REply

 

[Alchemist4lyf]

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

Yar. I haven't got any tips for you, mainly because no one else gave me any tips . But, thing is, just practice past papers. A lot of them. I've done quite a lot till now, so what I'll be doing today and tomorrow inshAllah, is I'll be practicing only the probability questions again. Because they're difficult, and I just can't master them. You do the same, or just practice the really recent ones. That's all I can say. =D

 

[Jai4ever]

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

ANY One Help in this question??????????????

 

[muzirox]

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

Correction = In section B, you do any 4 out of the 5 questions (7,8,9,10,11).

Thanx for correction

 

[muzirox]

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

ANY One Help in this question??????????????

It mean u've to calculate mean & s.d by the method of assumed mean for first part then for second you've to add that 299 to the mean obtained in first part & whereas s.d remains same in the second one.
hop u understand

 

[aleezay]

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

ANY One Help in this question??????????????

x : 299.3, 299.6, 299.9, 299.4, 299.1, 300.1, 300.6
f : 2 2 1 2 1 1 1

now,make a seperate column 4 X i.e (x-a) by subtracting 299 4m each ov these values.ul get :
X : 0.3, 0.6, 0.9, 0.4, 0.1, 1.1, 1.6
apply the formula : fX/f n ul get X's mean

4 standard deviation use d normal formula,taking X's values n ul gt d answer

 

[aleezay]

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

when locating d median 4 GROUPED data, is median (n/2)th term or (n+1/2)th term??