There are 40 scholars in a class, out of which 10 are sports- persons. Three scholars are selected at random out of them. Find the probability distribution for the selected persons who are sports-persons. Find the mean of the distribution.

There is a group of 50 people who are patriotic out of which 20 believe in non-violence. Two persons are selected at random out of them, write the probability distribution for the selected persons who are non-violent. Also find the mean of the distribution. Explain the importance of non-violence in patriotism.

(n>=5) persons are sitting in a row. Three of these are selected at random. The probability that no two of the selected persons sit together is

A class consists of 10 boys and 8 girls. Three students are selected at random. Find the probability that the selected group has : all Boys.

A class consists of 10 boys and 8 girls. Three students are selected at random. Find the probability that the selected group has : 2 boys and 1 girl.

A class consists of 10 boys and 8 girls. Three students are selected at random. Find the probability that the selected group has : all girls.

Find the mean of the following probability distribution of a random variable X

In a group of 30 scientists working on an experiment, 20 never commit error in their work and are reporting results elaborately. Two scientists are selected at random from the group. Find the probability distribution of the number of selected scientists who never commit error in work and reporting.

Find the mean and variance of the probability distribution of the number of sixes in three tosses of a die.

For a random variable X, sumXP(X)=1.5 , find the mean of probability distribution of X.