statistics difficult question

[vishal kumar]

can anyone plz explain me the following questions??

the question number and year is mentioned:

2008/paper 1/ q 8 part iv
2007/ paper 2 / q 2 part ii
2005/ paper 2 / q 4 part i and ii


plzz reply me as soon as possible.....

 

[soumayya]

N 2008 paper 1 Q 8(a)(iv)
P(visitor calls to see Claude)=0.4
P(only Claude at home)=P(Brian and Abdul not at home) * P(Claude not at home)
=0.8 * 0.7 * 0.4
=0.224
P(visitor calls to see Claude but Claude is the only one of the three not at home)=0.4 * 0.224
=0.0896

 

[soumayya]

N 2007 paper 2 Q 2(ii)

P(only A occurs)=0.3 - 0.18
=0.12

P(only B occurs)=0.6 - 0.18
=0.42

P(either A or B but not both occurs)=0.12 + 0.42
= 0.54

 

[soumayya]

N2005 paper 2 Q4

(i) A and B are mutually exclusive events:
P(A or B or both) = P(A) +P(B)
0.8 = p + 0.5
p = 0.3

(ii) P(A U B)= P(A) +P(B) - P(A intersection B)
P( A intersection B) = P(A) +P(B) - P(A U B)
= p +0.5 - 0.8

A and B are independent events:
P( A intersection B)=P(A) * P(B)
p + 0.5 - 0.8 = p * 0.5
p - 0.5p =0.8 -0.5
p = 0.3 / 0.5 =0.6

 

[OakMoon!]

Well answered