NCERT Class 12-Mathematics: Chapter –13 Probability Part 15
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Question 51:
The probability distribution of a random variable is given as under:
where is a constant. Calculate
(i)
(ii)
(iii)
Answer:
Otherwise | |||||||
We know that,
(i). So,
(ii) Also,
(iii)
Question 52:
A bag contains coins. It is known that n of these coins have a head on both sides whereas the rest of the coins are fair. A coin is picked up at random from the bag and is tossed. If the probability that the toss results in a head is determine the value of .
Answer:
Given, coin have head on both sides and coins are fair coins.
Let
Also,
Question 53:
Two cards are drawn successively without replacement from a well shuffled deck of cards. Find the mean and standard variation of the random variable where is the number of aces.
Answer:
Let denotes a random variable of number of aces.
Now,
We know that,
Also,