]> Answers to Selected Exercises

Answers to Selected Exercises

12. Finite Sampling Models

  1. Introduction
  2. The Hypergeometric Distribution
  3. The Multivariate Hypergeometric Distribution
  4. Order Statistics
  5. The Matching Problem
  6. The Birthday Problem
  7. The Coupon Collector Problem

1. Introduction

1.10.

  1. 1 1 1 2 1 3 1 4 2 1 2 2 2 3 2 4 3 1 3 2 3 3 3 4 4 1 4 2 4 3 4 4
  2. 1 2 1 3 1 4 2 1 2 3 2 4 3 1 3 2 3 4 4 1 4 2 4 3
  3. 1 1 1 2 1 3 1 4 2 2 2 3 2 4 3 3 3 4 4 4
  4. 1 2 1 3 1 4 2 3 2 4 3 4

1.11. 0.4162

1.12.

  1. 0.2070
  2. 0.1859

1.14.

  1. 0.9956
  2. No

1.15. 0.2635

1.16. 0.1633.

1.23.

  1. 14
  2. 1221
  3. 417
  4. 152

1.25. 0.000547

1.26.

  1. 11296
  2. 554
  3. 53888

1.28.

  1. 0.2937
  2. 0.7063

1.30.

  1. 189625
  2. 110000

1.31.

  1. 125
  2. 1225

2. The Hypergeometric Distribution

2.28. Let Y denote the number of defective chips in the sample

  1. Y k 10 k 90 5 k 100 5 for k 0 1 2 3 4 5
  2. Y 0.5 , Y 0.432 ,
  3. Y 0 0.416 ,

2.29. Let Y denote the number of women, so that Z 10 Y , is the number of men.

  1. Y k 30 k 20 10 k 50 10 for k 0 1 10
  2. Y 6 , Y 1.959 ,
  3. Z 4 , Z 1.959 ,
  4. Y 0 Y 10 0.00294 ,

2.30. Y denote the number of tagged fish in the sample

  1. Y k 100 k 900 20 k 1000 20 for k 0 1 20
  2. Y 2 , Y 196111
  3. Y 2 0.6108 ,
  4. Y 2 0.6083

2.31.

  1. Y k 10 k 0.4 k 0.6 10 k for k 0 1 10 .
  2. Y 4 , Y 2.4
  3. Y 5 0.3669

2.32. 20

2.33. 2000

2.34. 2000

2.35. Let U denote the number of spades and V the number of aces.

  1. U k 13 k 39 5 k 52 5 for k 0 1 5 , U 54 , U 235272
  2. V k 4 k 48 5 k 52 5 for k 0 1 4 , V 513 , V 9402873

2.36. Let U denote the number of hearts and V the number of honor cards.

  1. U k 13 k 39 13 k 52 13 for k 0 1 13 , U 134 , U 507272
  2. V k 16 k 36 13 k 52 13 for k 0 1 13 , V 4 , V 3617

3. The Multivariate Hypergeometric Distribution

3.15. Let X , Y , and Z denote the number of republicans, democrats, and independents, respectively, in the sample.

  1. X i Y j Z k 40 i 35 j 25 k 100 10 where i , j , and k are nonnegative integers with i j k 10 .
  2. X 4 , Y 3.5 , Z 2.5
  3. X 2.1818 , Y 2.0682 , Z 1.7045
  4. X Y 1.6364 , X Z 0.9091 , Y Z 0.7955
  5. 0.2474

3.16. Let X , Y , Z , U , and V denote the number of spades, hearts, diamonds, red cards, and black cards, respectively, in the hand.

  1. X i Y j Z k 13 i 13 j 13 k 13 13 i j k 52 13 where i , j , and k are nonnegative integers with i j k 13 .
  2. X i Y j 13 i 13 j 26 13 i j 52 13 where i and j are nonnegative integers with i j 13 .
  3. X i 13 i 39 13 i 52 13 for i 0 1 13 .
  4. U i V j 26 i 26 j 52 13 where i and j are nonnegative integers with i j 13 .

3.17. Let X , Y , and U denote the number of spades, hearts, and red cards, respectively, in the hand.

  1. X 134 , X 507272
  2. X Y -169272 ,
  3. U 132 , U 169272

3.18. Let X , Y , and Z denote the number of spades, hearts, and diamonds respectively, in the hand.

  1. X i Y j Z 4 13 i 13 j 22 9 i j 48 9 where i and j are nonnegative integers with i j 9 .
  2. X i Y 3 Z 2 13 i 34 8 i 47 8 for i 0 1 8 .

4. Order Statistics

4.16.

  1. X 5 3 k k 1 2 25 k 2 25 5 for k 3 4 22
  2. X 5 3 13
  3. X 5 3 1257 ,

4.17. 1437

4.19. 2322

5. The Matching Problem

5.29.

  1. k 0 1 2 3 4 5
    b 5 k 44 45 20 10 0 1
  2. k 0 1 2 3 4 5
    N 5 k 0.3667 0.3750 0.1667 0.0833 0 0.0083
  3. Covariance: 1100 , correlation 116

5.30.

  1. k N 10 k
    0 0.3678794
    1 0.3678791
    2 0.1839409
    3 0.0613095
    4 0.0153356
    5 0.0030555
    6 0.0005208
    7 0.0000661
    8 0.0000124
    9 0
    10 0.0000003
  2. N 10 1 , N 10 1
  3. N 10 3 0.0803

5.31.

  1. See 5.30 (a)
  2. k N k
    0 0.3678794
    1 0.3678794
    2 0.1839397
    3 0.0613132
    4 0.0153283
    5 0.0030657
    6 0.0005109
    7 0.0000730
    8 0.0000091
    9 0.0000014
    10 0.0000001

6. The Birthday Problem

6.7. 518

6.9. 89144

6.11. 189625

6.13. n 9

6.27.

  1. V 365 30 j 30 j k 0 j 1 k j k j k 365 30 for j 1 2 30
  2. V 365 30 28.8381
  3. V 365 30 1.0458
  4. V 365 30 28 0.89767

6.29.

  1. V 6 10 j 10 j k 0 j 1 k j k j k 6 10 for j 1 2 6
  2. V 6 10 5.0310
  3. V 6 10 0.5503
  4. V 6 10 4 0.22182

6.31.

  1. U 10 15 j 15 j k 0 10 j 1 k 10 j k 1 j k 10 15 for j 0 1 9
  2. V 10 15 2.0589
  3. V 10 15 0.9864
  4. V 10 15 3 0.3174

6.33.

  1. j 1 2 3
    V 4 3 j 116 916 616
  2. V 4 3 1 116
  3. V 4 3 3716
  4. V 4 3 0.6830

6.34.

  1. j 1 2 3 4 5
    V 10 5 j 110000 9272000 950 63127 189625
  2. V 10 5 4.095
  3. V 10 5 0.727

7. The Coupon Collector Problem

7.12. Let W W 365 40 denote the sample size.

  1. W n 364 39 j 0 39 1 j 39 j 39 j 365 n 1 for n 40 41
  2. W 42.3049
  3. W 2.4878
  4. t W i 1 40 366 i 365 i 1 t for t 36539

7.13. Let W W 6 6 denote the number of throws.

  1. W n j 0 5 1 j 5 j 5 j 6 n 1 for n 6 7
  2. W 14.7
  3. W 38.99
  4. W 10 0.7436

7.14. Let W W 10 10 denote the number of boxes purchased.

  1. W n j 0 9 1 j 9 j 9 j 10 n 1 for n 10 11
  2. W 29.2897
  3. W 125.6871
  4. W 15 0.04595