Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Trending News

Promoted
Hyrule
Hyrule asked in Science & MathematicsMathematics · 9 years ago

PROBABILITY S1 STATS HELP?

The question literally says

1.)The events A and B are independent and are that P(A)=0.4 AND P( A and B')= 0.3. EVALUATE P(B) and P(A U B)

and another one is

2.)The events A,B are such that P(A)=0.5 AND P(A U B) = 0.7

Find the value of P(B) when

a.) A and B are mutually exclusive

b.) A and B are independent

Another one asks

3.)A fair die is to be thrown ten times. Calculate the probability that:

a.) a score of 6 will be obtained exactly three times

b.) a score of 6 will be obtained for the third time on the tenth throw

Next question is:

4.)Bag A contains 4 red balls and 6 white balls, while bag B contain 3 red balls and 2 white balls. A bag is to be chosen from the outcome of tossing two fair coins; if two heads are tossed than bag A is chosen; otherwise bag B is chosen. From the chosen bag three balls are to be drawn at random without replacement.

a.) Calculate the probability that

i.) 3 red balls will be drawn

ii.) 2 red balls and 1 white ball will be drawn

b.) Given that 2 red balls and 1 white ball were drawn, find the probability that they came from bag A.

Guys, i know that this is alot but I AM LITERALLY BEGGING YOU TO SHOW ME HOW TO DO THIS PLSSSSSSS, if u cannot do all, plssss at least do questions 1 and 2 plssss.

1 Answer

Relevance
  • Anonymous
    9 years ago

    1.

    P(A and B') = P(A) - P(A and B)

    or, 0.3 =0.4 - P(A and B)

    or, P(A and B) = 0.1

    now if A and B are independent then

    P(A and B) = P(A) * P(B)

    or, 0.1 = 0.4 * P(B)

    or, P(B) = 0.25 ......... answer (i)

    now we know the formula,

    P(A U B) = P(A) + P(B) - P(A and B)

    or, P(A U B) = 0.4 + 0.25 - 0.1

    or, P(A U B) = 0.55 ................. answer (ii)

    2. a) when mutually exclusive P(A and B) = 0

    so,

    P(A U B) = P(A) + P(B) - P(A and B)

    or, 0.7 = 0.5 + P(B) - 0

    or, P(B) = 0.2

    b) when independent P(A and B) = P(A)*P(B)

    so,

    P(A U B) = P(A) + P(B) - P(A and B)

    or, P(A U B) = P(A) + P(B) - P(A)*P(B)

    or, 0.7 = 0.5 + P(B) - 0.5*P(B)

    or, 0.2 = 0.5*P(B)

    or, P(B) = 0.4

Still have questions? Get your answers by asking now.