
PROCEDURE FOR SELECTING RANDOM LOCATIONS FOR SAMPLING
By Doug Johnson, Extension EntomologistUniversity of Kentucky College of Agriculture
These figures are designed to help you remove your personal bias while selecting sampling points in a field. You will have to modify them to fit larger and smaller fields.
 Divide the field into general sampling areas.
 Randomly select one number between 1 and 100 for each general sampling area.
 Consult Table 2. 100 Sets of Random Site Selection Directions, under ENTRY NUMBER, to find the random
numbers you have selected. Record the set of walking instructions listed in the table for each of your random numbers.
 Select the first area of the field to be scouted.
 Go to the edge of that area. If this is a field edge go 30 paces into the field. This is your starting point.
 Use the walking instructions to locate your actual sample site.
 Take your sample.
As an example: let's look at a small corn field of 20 acres. According to the University of Kentucky IPM Scout Manual a field this size requires 3
samples to be taken.
 Divide the field into three general sampling areas.
 Select three random numbers say, 2, 31, 24.
 Look at Table 2 for Entry Numbers 2, 31, and 24 and you will find the following walking instructions:
Example Site Selection 

General Sampling Area  Entry Number  Direction  Left or Right  Paces  Left or Right  Paces Away 

1  2  Right  3  19 
2  31  Right  3  15 
3  24  Left  9  1 
 Select the first area to be scouted.
 Go to the edge of the first area. If it is a field edge go into the field 30 paces. From this starting point, follow the walking instructions for General Sampling Area 1 in the above table:
 Turn right, walk 3 paces, turn back to your original direction, take 19 paces, sample the area in front
of you.
 Go to the next general sampling area and repeat the process using the second set of walking
instructions (General Sampling Area 2 in the table above).
Through experience you will find that the number of paces specified may be too many or too few to use depending upon field
size. If the field is very large, simply multiply the number of paces by 10 or 100. If the field is very small, divide the number of paces by some number (e.g. 10) to keep you from running over the end of a sampling area.
Remember the objective is to remove bias from your selection of sites. There is nothing magic about these
numbers.
Table 2. 100 Sets of Random Site Selection Directions 

Entry Number  Direction  Left or Right  Paces  Left or Right  Paces Away 

1  Right  1  5 
2  Right  3  19 
3  Right  16  9 
4  Right  17  24 
5  Left  13  17 
6  Right  5  6 
7  Left  19  4 
8  Left  11  18 
9  Right  14  16 
10  Right  7  20 
11  Left  25  7 
12  Right  24  14 
13  Right  18  11 
14  Right  6  21 
15  Left  20  25 
16  Right  15  1 
17  Right  21  22 
18  Left  23  23 
19  Left  8  10 
20  Right  2  2 
Entry Number  Direction  Left or Right  Paces  Left or Right  Paces Away 

21  Left  22  13 
22  Right  16  8 
23  Right  12  3 
24  Left  9  12 
25  Left  4  15 
26  Right  2  6 
27  Right  12  13 
28  Left  11  22 
29  Right  7  11 
30  Right  4  14 
31  Right  3  15 
32  Right  21  3 
33  Left  16  4 
34  Right  19  17 
35  Left  5  8 
36  Right  6  19 
37  Left  24  9 
38  Right  23  5 
39  Right  25  1 
40  Right  15  23 
Entry Number  Direction  Left or Right  Paces  Left or Right  Paces Away 

41  Left  8  24 
42  Left  10  25 
43  Left  20  10 
44  Right  22  16 
45  Left  1  20 
46  Right  9  7 
47  Left  13  2 
48  Left  18  12 
49  Left  17  21 
50  Right  14  18 
51  Left  11  3 
52  Right  6  19 
53  Left  14  10 
54  Left  22  22 
55  Left  13  11 
56  Left  3  12 
57  Left  10  13 
58  Right  18  21 
59  Left  8  20 
60  Left  2  15 
Entry Number  Direction  Left or Right  Paces  Left or Right  Paces Away 

61  Right  12  18 
62  Left  4  8 
63  Right  21  6 
64  Right  15  24 
65  Right  24  4 
66  Left  5  13 
67  Left  23  23 
68  Left  7  14 
69  Left  19  11 
70  Left  25  1 
71  Left  20  25 
72  Right  1  12 
73  Right  16  8 
74  Left  17  7 
75  Right  9  19 
76  Left  10  24 
77  Right  6  6 
78  Left  7  15 
79  Left  8  5 
80  Left  17  21 
Entry Number  Direction  Left or Right  Paces  Left or Right  Paces Away 

81  Right  3  18 
82  Right  18  17 
83  Left  25  2 
84  Left  20  16 
85  Left  22  3 
86  Right  23  22 
87  Right  1  9 
88  Left  16  10 
89  Left  24  1 
90  Right  14  23 
91  Left  4  24 
92  Left  2  25 
93  Left  15  10 
94  Left  19  16 
95  Left  12  11 
96  Right  11  23 
97  Right  21  1 
98  Right  9  4 
99  Left  13  18 
100  Left  5  21 
Revised: 5/96
CAUTION! Pesticide recommendations in this publication
are registered for use in Kentucky, USA ONLY! The use of some products
may not be legal in your state or country. Please check with your local county
agent or
regulatory official before using any pesticide mentioned in this publication.
Of course,
ALWAYS READ AND FOLLOW LABEL DIRECTIONS FOR SAFE USE OF ANY
PESTICIDE!
This page is maintained by Pat Dillon, Department of Entomology, University of Kentucky.
Please send questions or suggestions to: pdillon@uky.edu
