Exam 1 Answers

[kido_1]

Same derivative graph here too.

[asa.hoshi]

any other thoughts on squareroot20 rather than 2squareroot5.

i think its good to simplify it. but i think they'll accept both answers.

HOW DO U DO QUESTION 6???
Pr(A) = 1/5
Pr(B) = 1/3
1. Find Pr(A' ^ B) given that Pr(A ^ B) = 1/8. [1mark]
2. Find Pr(A' ^ B) are mutually exclusive. [1mark]

^ - intersection. i can't find a key that offers a better symbol for it.

... something along those lines. i think i lost 2 marks because of those questions!   :x i thought it would be easy since it was worth 1 mark each. but i struggled with those 2 questions.

[maxleng]

for the Q where we had to find k, what if it wasnt simplified down fully? do you loose a mark for that?

edit: asa.hoshi draw vendiagrams,.. the boxes with circles in them and see where they intersect

[stussyitb]

what was question 8 again?

[Defiler]

any other thoughts on squareroot20 rather than 2squareroot5.

i think its good to simplify it. but i think they'll accept both answers.

HOW DO U DO QUESTION 6???
Pr(A) = 1/5
Pr(B) = 1/3
1. Find Pr(A' ^ B) given that Pr(A ^ B) = 1/8. [1mark]
2. Find Pr(A' ^ B) are mutually exclusive. [1mark]

^ - intersection. i can't find a key that offers a better symbol for it.

... something along those lines. i think i lost 2 marks because of those questions!   :x i thought it would be easy since it was worth 1 mark each. but i struggled with those 2 questions.

I got 5/24 ( as 1/3 - 1/8 )
and 1/3 ( as the places where A is not A and is intersected with B is just B )

prob wrong though.

[Collin Li]

HOW DO U DO QUESTION 6???
Pr(A) = 1/5
Pr(B) = 1/3
1. Find Pr(A' ^ B) given that Pr(A ^ B) = 1/8. [1mark]
2. Find Pr(A' ^ B) are mutually exclusive. [1mark]

^ - intersection. i can't find a key that offers a better symbol for it.

... something along those lines. i think i lost 2 marks because of those questions!   :x i thought it would be easy since it was worth 1 mark each. but i struggled with those 2 questions.

Code: [Select]

   A    A'
B            1/3
B'           2/3
   1/5  4/5  1

Fill in the table 2x2 grid in the table with whatever you're given.

Edit:
a) Pr(A' intersect B) = Pr(B) - Pr(A intersect B) = 1/3 - 1/8 = 8/24 - 3/24 = 5/24

b) Mutually exclusive means Pr(A intersect B) = 0
=> Pr(A' intersect B) = Pr(B) = 1/3

These were Year 11 Methods questions

[hifer]

any other thoughts on squareroot20 rather than 2squareroot5.

i think its good to simplify it. but i think they'll accept both answers.

HOW DO U DO QUESTION 6???
Pr(A) = 1/5
Pr(B) = 1/3
1. Find Pr(A' ^ B) given that Pr(A ^ B) = 1/8. [1mark]
2. Find Pr(A' ^ B) are mutually exclusive. [1mark]

^ - intersection. i can't find a key that offers a better symbol for it.

... something along those lines. i think i lost 2 marks because of those questions!   :x i thought it would be easy since it was worth 1 mark each. but i struggled with those 2 questions.

1. Pr(A' ^ B) = Pr(B) - Pr(A^B) = 1/3 - 1/8
2. Pr(A' ^ B) = Pr(B) = 1/3

[kido_1]

any other thoughts on squareroot20 rather than 2squareroot5.

i think its good to simplify it. but i think they'll accept both answers.

HOW DO U DO QUESTION 6???
Pr(A) = 1/5
Pr(B) = 1/3
1. Find Pr(A' ^ B) given that Pr(A ^ B) = 1/8. [1mark]
2. Find Pr(A' ^ B) are mutually exclusive. [1mark]

^ - intersection. i can't find a key that offers a better symbol for it.

... something along those lines. i think i lost 2 marks because of those questions!   :x i thought it would be easy since it was worth 1 mark each. but i struggled with those 2 questions.

I really hated those 2 buggered questions. I think i might have got 1/2.

[Daniel15]

any other thoughts on squareroot20 rather than 2squareroot5.

i think its good to simplify it. but i think they'll accept both answers.

HOW DO U DO QUESTION 6???
Pr(A) = 1/5
Pr(B) = 1/3
1. Find Pr(A' ^ B) given that Pr(A ^ B) = 1/8. [1mark]
2. Find Pr(A' ^ B) are mutually exclusive. [1mark]

^ - intersection. i can't find a key that offers a better symbol for it.

... something along those lines. i think i lost 2 marks because of those questions!   :x i thought it would be easy since it was worth 1 mark each. but i struggled with those 2 questions.

I guessed those
I think if they're mutually exclusive, then Pr(A' ∩ B) = Pr(A') * Pr(B).

And for the first bit, I did Pr(B) - Pr(A ∩ B). No clue whether that's right though, it was only a guess.

Edit: Oops, looks like I screwed them up  :oops:

[hifer]

HOW DO U DO QUESTION 6???
Pr(A) = 1/5
Pr(B) = 1/3
1. Find Pr(A' ^ B) given that Pr(A ^ B) = 1/8. [1mark]
2. Find Pr(A' ^ B) are mutually exclusive. [1mark]

^ - intersection. i can't find a key that offers a better symbol for it.

... something along those lines. i think i lost 2 marks because of those questions!   :x i thought it would be easy since it was worth 1 mark each. but i struggled with those 2 questions.

Code: [Select]

   A    A'
B            1/3
B'           2/3
   1/5  4/5  1

Fill in the table 2x2 grid in the table with whatever you're given.

Hey coblin, does that also work if A&B are mutually exclusive?

[kido_1]

any other thoughts on squareroot20 rather than 2squareroot5.

i think its good to simplify it. but i think they'll accept both answers.

HOW DO U DO QUESTION 6???
Pr(A) = 1/5
Pr(B) = 1/3
1. Find Pr(A' ^ B) given that Pr(A ^ B) = 1/8. [1mark]
2. Find Pr(A' ^ B) are mutually exclusive. [1mark]

^ - intersection. i can't find a key that offers a better symbol for it.

... something along those lines. i think i lost 2 marks because of those questions!   :x i thought it would be easy since it was worth 1 mark each.

but i struggled with those 2 questions.

I think i did the same as you for the non mutually exclusive. I am pretty sure part a was 5/24.
I guessed those
I think if they're mutually exclusive, then Pr(A' ∩ B) = Pr(A') * Pr(B).

And for the first bit, I did Pr (A ∩ B) - Pr(A). No clue whether that's right though, it was only a guess.

[Daniel15]

And for the first bit, I did Pr (A ∩ B) - Pr(A). No clue whether that's right though, it was only a guess.

Oops, I wrote it wrong, I actually did Pr(B) - Pr(A ∩ B), which looks correct. Edited my post

[stussyitb]

what was question 8 again guys??
cheers

[Collin Li]

Hey coblin, does that also work if A&B are mutually exclusive?

Yeah. You just fill in the A intersect B part with 0. They should have asked Pr(A' intersect B'). That would have been interesting. I think some students would have got confused and put 1 even, haha.

[asa.hoshi]

i never liked those kind of questions. hated it with a passion.