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Statistics

Notes 7.7 Review Questions

1. What is the probability of getting exactly two heads in three throws of an unbiased coin?
2. What is the probability of getting a sum of 2 or 8 or 12 in single throw of two unbiased
dice?
3. Two cards are drawn at random from a pack of 52 cards. What is the probability that the
first is a king and second is a queen?

4. What is the probability of successive drawing of an ace, a king, a queen and a jack from a
pack of 52 well shuffled cards? The drawn cards are not replaced.
5. 5 unbiased coins with faces marked as 2 and 3 are tossed. Find the probability of getting a
sum of 12.
6. If 15 chocolates are distributed at random among 5 children, what is the probability that a
particular child receives 8 chocolates?
7. A and B stand in a ring with 10 other persons. If arrangement of 12 persons is at random,
find the chance that there are exactly three persons between A and B.

8. Two different digits are chosen at random from the set 1, 2, 3, 4, 5, 6, 7, 8. Find the
probability that sum of two digits exceeds 13.
9. From each of the four married couples one of the partner is selected at random. What is the
probability that they are of the same sex?
10. A bag contains 5 red and 4 green balls. Two draws of three balls each are done with
replacement of balls in the first draw. Find the probability that all the three balls are red
in the first draw and green in the second draw.
11. Two dice are thrown two times. What is the probability of getting a sum 10 in the first and
11 in the second throw?
12. 4 cards are drawn successively one after the other without replacement. What is the
probability of getting cards of the same denominations?

Answers: Self Assessment

1. (a) 2. (b) 3. (d) 4. (d) 5. (c) 6. (b)

7.8 Further Readings

Books Introductory Probability and Statistical Applications by P.L. Meyer
Introduction to Mathematical Statistics by Hogg and Craig
Fundamentals of Mathematical Statistics by S.C. Gupta and V.K. Kapoor

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