Stats1 made easier! Just have a look at this!

[princessazru]

AN IMPORTANT QUESTION
1. Calculate the total mean when E(x-5)=226, N=38
Mean(x-5)=226/38
=5.95
Therefore, Mean(x)=5.95+5
=11.O

2. Calculate the total variance when E(x-2)^2=200, E(x-2)=22,N=5
Variance(x-2)=(2OO/5)-(22/5)^2
=20.6
Therefore, Variance(x)=20.6
Note: In this case we do not have to add 2 like in question 1.
So, Var(x)=Var(x-a)=Var(x+a) unlike the case in mean

Also,S.D(x)=S.D(x-a)=S.D(x=a)

3. The standard deviation of the three numbers a,b,c is 3.2
a. State the standard deviation of the three numbers 3a,3b,3c.
b. State the standard deviation of the three numbers a+2,b+2,c+2
c. State the standard deviation of the three numbers 2a+5,2b+5,2c+5

Ans: a. 3.2 X 3 = 9.6 b. 3.2 c. 3.2 X 2 = 6.4

Hope, you’ve understood.

wat do u mean by S.D(x=a)?
did u mean S.D(x+a) ?

Yes, i meant S.D. (x+a)!! Sorry!!

 

[BILALrox01]

Ahan.. this is not stats made easier.. Stats could only be made easier by removing perms and combs from the paper

 

[robotic94]

Ahan.. this is not stats made easier.. Stats could only be made easier by removing perms and combs from the paper

haha so true ^^

anyone wanting to help in this , how to figure out whether its a P or a C? when do we use a P and a C , i never got that any help on this

thnakyou sooo much !

 

[Banglarbagh]

Ahan.. this is not stats made easier.. Stats could only be made easier by removing perms and combs from the paper

haha so true ^^

anyone wanting to help in this , how to figure out whether its a P or a C? when do we use a P and a C , i never got that any help on this

thnakyou sooo much !

Permutation is simply way of arrngement, and combination is way of selection, read the question carefully figure it out wt is it askin u to do.??? do arrngment or do selecton ..??? sometymes both of them r together..!!

 

[AayushR]

Can you do something similar for Stats 2?

 

[ahmed t]

do we have to know combinations with repetition

 

[BILALrox01]

Actually distinguishing between them isn't that difficult. Just read the question and If u got a grade in English you should be able to identify. However the problem comes when the performance of the question comes.. I always leave 1 part lik multply by 2 or these are to b added not multiplied. Nd know I have yet to see com with repetition.If I remember correctly cuz have been out of touch for so long.

 

[ahmed t]

i never knew we needed to know it cause ive never seen it before any where

 

[samy]

how do v know wen v have to add and wen to multiply in comb n permu?

 

[BILALrox01]

By checking the MS :lol: cuz i doubt k koi teacher b aise sawal pehli go mai bilkul correct kar sakta hai.

 

[bineetojha]

thank you..

 

[samy]

By checking the MS :lol: cuz i doubt k koi teacher b aise sawal pehli go mai bilkul correct kar sakta hai.

lol..!!! the comb permu quest even cant do them rite wen consulting mark scheme....
yea man datx the prob no teacher here is gud enuf to make my conceptx clear about this topic :S :S :evil: :evil:

 

[BILALrox01]

Well actually jab teacher khud ek ghanta smajh k ap ko samjhata hai na to banda sochta hai k it was so easy.. Nyways aar paper ka tym thora sa zada ho to 15 marks k question mai 12 to aa hi jatai hain

 

[samy]

Well actually jab teacher khud ek ghanta smajh k ap ko samjhata hai na to banda sochta hai k it was so easy.. Nyways aar paper ka tym thora sa zada ho to 15 marks k question mai 12 to aa hi jatai hain

letx stop bugging teacherx :lol: :lol: :lol:

tell me how to prepare for s1...esp this sick topic!

 

[Amna]

simple permutations and combinations are fine if u practice them a little, i find the "box approach" very useful. i can solve any question on that. but what i don't get, at all, is permutations and combinations with repetition. the syllabus clearly states u don't need to know them, my teacher said you don't need to know them, but somebody pointed them out in recent papers. it doesn't make any sense!

 

[BILALrox01]

Pichlai puranai to ho jatai hain magar last year walai to buhat pharo thai.. Whats tthis box approach

 

[ahmed t]

simple permutations and combinations are fine if u practice them a little, i find the "box approach" very useful. i can solve any question on that. but what i don't get, at all, is permutations and combinations with repetition. the syllabus clearly states u don't need to know them, my teacher said you don't need to know them, but somebody pointed them out in recent papers. it doesn't make any sense!

What is this box approach method?
and for the comb and perm with repetition i just searched it up in the internet and memorised the formulas just incase it comes, and yea its not in the syllabus of 2007

 

[XPFMember]

Assalamoalaikum!!

Well people please use 'English' here around the forum, so that it is easy and simple for all people to understand!

I hope you get it!

Take care next time regarding this matter!

Thanks,
мαтн αпgεʟ

 

[BILALrox01]

plz elaborate.. Y shld we use English only??

 

[ahmed t]

cause not every1 is pakistany, for example me