Statistics Paper 62 -- How was it?!

[Bushrafareed]

How did you do it?

It's same thing what you apply in binomial question. Applying 4C2 here means that from 4 turns in which turn he'll get exactly 2 unwrapped biscuits

 

[Jaf]

its the correct method. multiply by 4C2 or by 4!/(2!*2!). as there r two wrapped and two unwrapped

Oh lol sorry. I meant 4!/2!*2!.

 

[Ahmed Tariq]

yes, i'm sure. I checked this method from marking scheme for without replacement questions.

Yes, it is indeed correct. The correct answer was supposed to be 0.368, and it gives exactly that.
I made a horrendous error. What I did was write 4C2*(18/30)*(17/29)*(12/30)*(11/29) and got the answer 0.320. I must have been blind or something. Do you expect I'd get any marks out of 4? 2 maybe?

 

[Ahmed Tariq]

It's not. You're supposed to multiply the entire thing by 4!/2! instead of 4C2.

Isn't 4!/2! and 4C2 both equal to 6?

 

[Silent Hunter]

Isn't 4!/2! and 4C2 both equal to 6?

nope.... 4!/2! is 12 not 6

 

[Ahmed Tariq]

nope.... 4!/2! is 12 not 6

Yeah, my bad but a lot of people who did this question by probability or by drawing a tree diagram got the same answer.

 

[Silent Hunter]

Yeah, my bad but a lot of people who did this question by probability or by drawing a tree diagram got the same answer.

yeah

 

[redapple20]

5154 sumthing or maybe 5514

 

[redapple20]

Is may binomial use. Karna tha Na?

 

[Bushrafareed]

Exactly, you 'll get around 2 to 3 marks

Yes, it is indeed correct. The correct answer was supposed to be 0.368, and it gives exactly that.
I made a horrendous error. What I did was write 4C2*(18/30)*(17/29)*(12/30)*(11/29) and got the answer 0.320. I must have been blind or something. Do you expect I'd get any marks out of 4? 2 maybe?

 

[imagine]

though lost 7 marks, it was actually good

 

[gadagada]

was ans to q1 was something like , 2154?

i got the answer 5514.. i wonder who is correct...

 

[Bushrafareed]

i got the answer 5514.. i wonder who is correct...

Okay i don't remember exactly but it could be something similar to you..

 

[AGEG]

I got 5508.5 for Q1 :s

 

[Sammar]

I got 5514 for Q1

 

[AGEG]

What did you get for the standard deviation?

 

[AGEG]

What did you get for the standard deviation?

Was it 6.06025?

 

[Silent Hunter]

Was it 6.06025?

smthng like that

 

[Ahmed_19_94]

then how did everyone get 5514?

 

[Ahmed_19_94]

smthng like that

it is 5508.5 or 5509