In a series of 2 n observations, half of them equal ‘a’ and remaining half equal – a. If the standard deviation of the observations is 2, then  a  equals ……
Let X be a random variable whose possible values x_{1}, x_{2}, x_{3}, …, x_{n} occur with probabilities p_{1}, p_{2}, p_{3},…, p_{n}, respectively. The mean of X, denoted by
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The number of adults living in homes on a randomly selected city block is described by the following probability distribution.
What is the probability that 4 or more adults reside at a randomly selected home?
Two dice are thrown simultaneously. If X denotes the number of sixes, then the expectation of X is:
Let X be a random variable whose possible values x_{1}, x_{2}, x_{3}, …, x_{n} occur with probabilities p_{1}, p_{2}, p_{3},…, p_{n}, respectively. Also, μ be the mean of X. The variance of X, denoted by Var (X) is defined as
The variance of the number obtained on a throw of an unbiased dice is:
The mean number of tails in three tosses of a fair coin is:
A class has 10 students whose ages are 15, 14, 16, 17, 19, 20, 16, 18, 20, and 20 years. One student is selected in such a manner that each has the same chance of being chosen and the age X of the selected student is recorded. The standard deviation of X is:
Let X be a random variable whose possible values x_{1}, x_{2}, x_{3}, …, x_{n} occur with probabilities p_{1}, p_{2}, p_{3},…, p_{n}, respectively. Also, E(X) is the expectation of X, then E(X^{2})  [E(X)]^{2} is known as
In a meeting, 60% of the members favour and 40% oppose a certain proposal. A member is selected at random and we take X = 0 if he opposed, and X = 1 if he is in favour. Find E(X) and Var(X).
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204 videos288 docs139 tests
