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A class has 15 students whose ages are 1...

A class has 15 students whose ages are 14, 17, 15, 14, 21, 17, 19, 20, 16, 18, 20, 17, 16, 19 and 20 years. One student is selected such a manner that each has the same chance of being chosen and the age X of the selected student is recorded. What is the probability distribution of the random variable X? Find mean, variance and standard deviation of X.

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The correct Answer is:
Variance = 4.18 and standard deviation= 2.19
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NEW JOYTHI PUBLICATION-PROBABILITY-SOLUTIONS TO NCERT TEXT BOOK EXERCISE 13.4
  1. State which of the following are not the probability distributions of ...

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  2. An urn contains 5 red and 2 black balls . Two balls are randomly draw...

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  3. Let X represent the difference between the number of head and the numb...

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  4. Find the probability distribution of i. number of head in two tosse...

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  5. Find the probability distribution of the number of successes in two to...

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  6. From a lot of 30 bulbs which include 6 defectives, a sample of 4 bulbs...

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  7. A coin is biased so that the head is 3 times as likely to occur as tai...

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  8. A random variable X has the following probability distribution. ...

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  9. The random variable X has a probability distribution P(X) of the follo...

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  10. Find the mean number of heads in three tosses of a fair coin.

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  11. Two dice are thrown simultaneously. If X denotes the number of sixes, ...

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  12. Two numbers are selected at random (without replacement) from the firs...

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  13. Let X denote the sum of the numbers obtained when two fair dice are ro...

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  14. A class has 15 students whose ages are 14, 17, 15, 14, 21, 17, 19, 20,...

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  15. In a meeting, 70% of the members favour and 30% oppose a certain propo...

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  16. The mean of the numbers obtained on throwing a die having written 1 on...

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  17. Suppose that two cards are drawn at random from a deck of cards. Let X...

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