Recent questions in Probability

Given P(A) = 0.3, P(B) = 0.2, Find P(B/A) if A and B are mutually exclusive events.

asked Feb 5, 2013 by meena.p

5 answers

A die is thrown 120 times and getting 1 or 5 is considered success. Find the mean, variance of number of successes.

asked Feb 5, 2013 by meena.p

0 answers

Urn A contain 1 white, 2 black, 3 red balls. Urn B contain 2 white, 1 black, 1 red balls. Urn C contains 4 white, 5 black, 3 red balls. Two balls are drawn from one of the Urn and found to be one white and one red. Find the probabilities that they come from Urns A, B or C.

asked Feb 5, 2013 by meena.p

0 answers

Let A and B be two events.If P(A|B)=P(A),then A is______of B.

asked Jan 10, 2013 by sreemathi.v

0 answers

Let X be a random variable taking values $x_1,x_2,.....,x_n$ with probabilities $p_1,p_2,......,p_n$,respectively.Then var(X)=________.

asked Jan 10, 2013 by sreemathi.v

0 answers

If X follows binomial distribution with parameters n=5,p and P(x=2)=9,P(X=3),then p=__________.

asked Jan 10, 2013 by sreemathi.v

0 answers

If A and B are such that \[P(A'\cup B')=\frac{2}{3} \;and\;P(A\cup B)=\frac{5}{9},\]\[then\;P(A')+P(B')=\text{__________}.\]

asked Jan 10, 2013 by sreemathi.v

1 answer

If A and B are two events such that $P(A|B)=p,P(A)=p,P(B)=\frac{1}{3} \quad$ and $\quad P(A\cup B)= \frac{5}{9},$ then $\; p=\text{_____________}.$?

asked Jan 10, 2013 by sreemathi.v

1 answer

True or False: If A,B and C are three independent events such that P(A)+P(B)=P(C)=p,then\[P(At\;least\;two\;of\;A,B,C\; occur)=3p^2-2p^3\]

asked Jan 10, 2013 by sreemathi.v

1 answer

True or False: If A and B are two events such that P(A)>0 and P(A)+P(B)>1,then\[P(B|A)\geq 1-\frac{p(B')}{P(A)}\]

asked Jan 10, 2013 by sreemathi.v

1 answer

True or False: If A and B are independent,then \[P(exactly\; one\; of \;A,B\; occurs)=P(A)P(B)+P(B)P(A)\]

asked Jan 10, 2013 by sreemathi.v

1 answer

True or False: If A and B are independent events,then $P(A'\cup B)=1-P(A)(B')$

asked Jan 10, 2013 by sreemathi.v

1 answer

True or False: Another name for the mean of a probability distribution is expected value.

asked Jan 10, 2013 by sreemathi.v

1 answer

True or False: If A and B are two independent events then P(A and B)=P(A).P(B).

asked Jan 10, 2013 by sreemathi.v

1 answer

True or False: Two independent events are always mutually exclusive.

asked Jan 10, 2013 by sreemathi.v

1 answer

True or False: If A and B are mutually exclusive events,then they will be independent also.

asked Jan 10, 2013 by sreemathi.v

1 answer

True or False: If A and B are independent events,then A and B are also independent.

asked Jan 10, 2013 by sreemathi.v

1 answer

True or False: Let P(A)>0 and P(B)>0.Then A and B can be both mutually exclusive and independent.

asked Jan 10, 2013 by sreemathi.v

1 answer

A box has 100 pens of which 10 are defective.What is the probability that out of sample of 5 pens drawn one by one with replacement at most one is defective?

asked Jan 10, 2013 by sreemathi.v

1 answer

A and B are two students.Their chances of solving a problem correctly are $\Large\frac{1}{3}$ and $\Large\frac{1}{4}$,respectively.If the probability of their making a common error is ,$\Large\frac{1}{20}$ and they obtain the same answer,then the probability of their answer to be correct is

asked Jan 10, 2013 by sreemathi.v

1 answer

In a college,30% students fail in physics,25% fail in mathematics and 10% fail in both.One student is chosen at random.The probability that she fails in physics if she has failed in mathematics is

asked Jan 10, 2013 by sreemathi.v

1 answer

Suppose a random variable X follows the binomial distribution with parameters n and p,where 0 < p < 1.If P(x=r)/P(x=n-r) is independent of n and r ,then P equals

asked Jan 10, 2013 by sreemathi.v

1 answer

For the following probability distribution:

asked Jan 10, 2013 by sreemathi.v

1 answer

For the following probability distribution:

asked Jan 10, 2013 by sreemathi.v

1 answer

The probability distribution of a discrete random variable X is given below:

asked Jan 10, 2013 by sreemathi.v

1 answer

The probability that a person is not swimmer is 0.3.The probability that out of 5 persons 4 are swimmers is

asked Jan 10, 2013 by sreemathi.v

1 answer

The probability of guessing correctly at least 8 out of 10 answers on a true-false type examination is

asked Jan 10, 2013 by sreemathi.v

1 answer

Two cards are drawn from a well shuffled deck of 52 playing cards with replacement.The probability,that both cards are queens ,is

asked Jan 10, 2013 by sreemathi.v

1 answer

Which one is not a requirement of a binomial distribution?

asked Jan 10, 2013 by sreemathi.v

1 answer

Two dice are thrown.If it is known that the sum of numbers on the dice was less than 6,the probability of getting a sum 3,is

asked Jan 10, 2013 by sreemathi.v

1 answer

Eight coins are tossed together.The probability of getting exactly 3 heads is

asked Jan 10, 2013 by sreemathi.v

1 answer

A flash light has 8 batteries out of which 3 are dead.If two batteries are selected without replacement and tested,the probability that both are dead is

asked Jan 10, 2013 by sreemathi.v

1 answer

A box contains 3 orange balls,3 green balls and blue balls.three balls are drawn at random from the box without replacement .The probability of drawing 2 green balls and one blue ball is

asked Jan 10, 2013 by sreemathi.v

1 answer

A die is thrown and a card is selected at random from a deck of 52 laying cards.The probability of getting an even number on the die and a spade card is

asked Jan 10, 2013 by sreemathi.v

1 answer

Assume that in a family,each child is equally likely to be a boy or a girl.A family with three children is chosen at random.The probability that the eldest child is a girl given that the family has at least one girl is

asked Jan 10, 2013 by sreemathi.v

1 answer

Three persons,A,B and C,fire at a target in turn,starting with A.Thier probability of hitting the target are 0.4,0.3 and 0.2 respectively.The probability of two hits is

asked Jan 10, 2013 by sreemathi.v

1 answer

A bag contains 5 red and 3 blue balls.The probability that exactly two of the three balls were red,the first ball being red,is

asked Jan 10, 2013 by sreemathi.v

1 answer

A bag contains 5 red and 3 blue balls.If 3 balls are drawn at random without replacement the probability of getting exactly one red ball is

asked Jan 10, 2013 by sreemathi.v

1 answer

Two events E and F are independent.If $P(E)=0.3,P(E\cup F)=0.5$,then P(E|F) - P(F|E) equals

asked Jan 10, 2013 by sreemathi.v

0 answers

If the events A and B are independent ,then $P(A\cap B)$ is equal to

asked Jan 10, 2013 by sreemathi.v

1 answer

Let A and B be two events .Such that $P(A)=\Large\frac{3}{8}$,$P(B)=\Large \frac{5}{8}$ and $P(A\cup B)=\Large\frac{3}{4}$.Then P(A|B).P(A|B) is equal to

asked Jan 10, 2013 by sreemathi.v

1 answer

If two events are independent,then

asked Jan 10, 2013 by sreemathi.v

1 answer

If A and B are two independent events with $P(A)=\Large \frac{3}{5}$ and $P(B)=\Large \frac{4}{9},$then $P(A\cap B)$ equals

asked Jan 10, 2013 by sreemathi.v

1 answer

If A and B are such events that $P(A)>o$ and $P(B)\neq 1$,then P(A|B) equals

asked Jan 10, 2013 by sreemathi.v

1 answer

Let $P(A)=\Large\frac{7}{13}$,$P(B)=\Large\frac{9}{13}$ and $P(A\cap B)=\Large\frac{4}{13}$. Then P(A|B) is equal to

asked Jan 10, 2013 by sreemathi.v

1 answer

If A and B are two events such that $P(A)=\Large\frac{1}{2},\normalsize P(B)=\Large\frac{1}{3},\normalsize P(A/B)=\Large \frac{1}{4},$then $P(A'\cap B')$ equals

asked Jan 10, 2013 by sreemathi.v

1 answer

If $P(A)=\Large\frac{2}{5},\normalsize P(B)=\Large\frac{3}{10}$ and $P(A\cap B)=\Large\frac{1}{5},$then P(A|B).P(B'|A') is equal to

asked Jan 10, 2013 by sreemathi.v

1 answer

If $P(A)=\Large\frac{3}{10},\normalsize P(B)=\Large\frac{2}{5}$ and $P(A\cap B)=\Large\frac{3}{5},$then $P(B|A)+P(A|B)$ equals

asked Jan 10, 2013 by sreemathi.v

1 answer

If $P(A\cap B)=\Large\frac{7}{10}$,and $P( B)=\Large\frac{17}{20}$,then P(A|B) is equals

asked Jan 10, 2013 by sreemathi.v

1 answer

If $P(A)=\Large\frac{4}{5}$,and $P(A\cap B)=\Large\frac{7}{10}$,then P(B|A) is equal to

asked Jan 10, 2013 by sreemathi.v

1 answer

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