In a population it is estimated that 20 have a desired trait

In a population it is estimated that 20% have a desired trait of interest for the researcher. The researcher wants to know how many people on average he has to draw from a population to get 2 people with the trait. Use rows 20-24 of the Random Number Table to carry out the simulation. Explain clearly how you set up the problem and report your findings.

Row 20

39634 62349 74088 65564 16379 19713 39153 69459 17986 24537

14595 35050 40469 27478 44526 67331 93365 54526 22356 93208

30734 71571 83722 79712 25775 65178 07763 82928 31131 30196

64628 89126 91254 24090 25752 03091 39411 73146 06089 15630

42831 95113 43511 42082 15140 34733 68076 18292 69486 80468

Row 25

80583 70361 41047 26792 78466 03395 17635 09697 82447 31405

00209 90404 99457 72570 42194 49043 24330 14939 09865 45906

05409 20830 01911 60767 55248 79253 12317 84120 77772 50103

95836 22530 91785 80210 34361 52228 33869 94332 83868 61672

65358 70469 87149 89509 72176 18103 55169 79954 72002 20582

Row 30

72249 04037 36192 40221 14918 53437 60571 40995 55006 10694

41692 40581 93050 48734 34652 41577 04631 49184 39295 81776

61885 50796 96822 82002 07973 52925 75467 86013 98072 91942

48917 48129 48624 48248 91465 54898 61220 18721 67387 66575

88378 84299 12193 03785 49314 39761 99132 28775 45276 91816

Row 35

77800 25734 09801 92087 02955 12872 89848 48579 06028 13827

24028 03405 01178 06316 81916 40170 53665 87202 88638 47121

86558 84750 43994 01760 96205 27937 45416 71964 52261 30781

78545 49201 05329 14182 10971 90472 44682 39304 19819 55799

14969 64623 82780 35686 30941 14622 04126 25498 95452 63937

Row 40

58697 31973 06303 94202 62287 56164 79157 98375 24558 99241

38449 46438 91579 01907 72146 05764 22400 94490 49833 09258

62134 87244 73348 80114 78490 64735 31010 66975 28652 36166

72749 13347 65030 26128 49067 27904 49953 74674 94617 13317

Solution

If the probability of a person with the trait is 1/5 , to get two people with that trait , we should sample 10 people.
10(1/5) = 2
We do not know how many people there are in the population. Assume 1000.
We need 10 random numbers
Start anywhere.
I start at 74088 -- you may choose anywhere.
The first person is 740
The second: 886
The third: 556
The fourth: 416 etc. until you choose 10.

If the original population was 10,000, you must choose ten 5-digit numbers. You may start anywhere and keep going right.

Begin at 65564
unit 1- 6556
unit 2 - 4163
unit 3 - 7919