GRASSHOPPER EGG-POD DISTRIBUTION 
5 
Table 2. Mean egg-pod populations per square foot in fields and margins 
in 10 counties in north-central Montana in 1940. (Five field and 2 mar¬ 
ginal locations were sampled at each of 70 different places in each county) 
County 
Field locations 1 
Marginal locations 
1 
2 
3 
4 
5 
Near road 
Near field 
Blaine. 
0.80 
0.33 
0.56 
0.63 
0.63 
0.75 
0.89 
Cascade. 
.48 
.44 
.64 
.86 
.30 
.56 
.72 
Chouteau. 
.64 
.64 
.36 
.33 
.34 
.79 
1.00 
Fergus. 
.62 
.30 
.32 
.38 
.46 
.48 
.84 
Hill. 
.20 
.26 
.42 
.50 
.64 
.82 
1.56 
Judith Basin. 
.14 
.04 
.10 
.19 
.04 
.06 
.10 
Liberty. 
.34 
.23 
.46 
.43 
.36 
.55 
.80 
Pondera. 
.56 
.79 
.66 
.96 
.89 
2.50 
2.91 
Teton. 
.59 
.67 
.49 
.49 
.63 
1.85 
1.90 
Toole. 
.34 
.34 
.53 
.39 
.44 
.43 
.58 
Average. 
.47 
.40 
.45 
.52 
.47 
.88 
1.13 
Locations designated by numbers: (1) Edge of field; (2) one-fourth of the distance to center of field; 
(3) one-half of the distance to center of field; (4) three-fourths of the distance to center of field; (5) center 
of field. 
To obtain further information on the effect of sample location, the 
data were studied by an analysis of variance. The results are shown in 
table 3. The arrangement of the sampling makes it possible to study the 
Table 3. —Variance in numbers of egg pods per square foot between fields, 
between locations within fields, and between units within locations, for 10 
counties in north-central Montana in 1940 (degrees of freedom given in 
parentheses in column heading) 
County 
Between 
fields 
(69) 
Between 
locations 
(4) 
Interaction, 
field and 
location (276) 
Units within 1 
locations 
(350) 
Blaine. 
n.oi 
3 1.02 
0.33 
0.42 
Cascade. 
2 .93 
3 1.60 
3 .50 
. 35 
Chouteau. 
2 .80 
3 .93 
.31 
.36 
Fergus. 
3 .50 
.63 
.30 
.32 
Hill. 
2 1.07 
1.03 
.45 
.42 
Judith Basin. 
3 .09 
3 .14 
.05 
.07 
Liberty. 
2 .37 
.28 
.24 
.16 
Pondera. 
2 .60 
.92 
.42 
.38 
Teton. 
2 1.44 
.25 
2 .82 
.47 
Toole. 
2 .68 
.22 
.18 
,24 
‘Interaction, field and location, is typically error for location; units is error for interaction and for fields 
in comparing variances by the F test. 
Significant at 1-percent level of probability. 
Significant at 5-percent level of probability. 
over-all effect of given locations in the field, as well as the interaction or 
differential effect of location from field to field. The variation between 
units, as shown within pairs at each location, can also be studied. As 
