192
Methods of Yoking Bullocks
As we neared the end of the first series of tests, an
attempt was made to analyse the results. The
results were averaged, plotted in various ways and
studied statistically. There appeared to be quite
significant differences between the pairs of bullocks,
but the differences between the yokes were not statisti-
cally significant. Study of the data seemed to indi-
cate that it did not prove the lack of difference be-
tween yokes, but rather that our testing had not
been under sufficiently controlled conditions, parti-
cularly with regard to the handling of the bullocks.
The data showed too great difference between the
high and low readings, indicating that in some cases
the bullocks had exerted abnormal effort and that
in others they had shirked. Results of every test
had been recorded in an attempt to avoid anything
which might resemble 'doctoring' the datta. The
effect was somewhat that of including in a series of
analyses for nitrogen, samples into which had flies
in the course of the digestion.
Whether to include any given test or not presented
a real difficulty. Obviously, when the bullocks ran
and came up at the end of the test with a jerk, the
maximum pull would be abnormal and it was easy
to discard such test. Tests when the bullocks shirked
were more difficult. Determining the standard of
urging to be used was not easy. It might vary all
the way from whispered commands to severe beating.
This seemed to be the biggest variable and the most
difficult to control. It seemed definite that we should
not determine which data to record by the magnitude
of the reading. It was decided therefore, after
consulting with Dr Sukhatme, Statistician of the
Imperial Council of Agricultural Research, to again
run through the tests, using a fewer number of trials
of each yoke and attempting to control the conditions
more carefully. We decided to try to determine
which trials to discard before reading the dynamo-
meter scale by carefully watching the animals during
the test.
We therefore randomized the order in which the
yokes were to be tested and ran the whole 15 again,
making only five tests on each yoke and using one
pair of bullocks. When this series of tests was
completed and the results were studied, it appeared
that they were more consistent than the first
series. To make sure, we again ran a similar series
of tests, with a new randomization order, making
five tests each. Three such replications were made
to see if we could duplicate the results. The results
of the replications were consistent, showing only the
variation which would be reasonable when working
with animals. The results of the three replications of
five tests with each pair of bullocks were combined,
TABLE 1
Average pull of bullock with double yokes
Bullocks
Team No.
34 & 35 . .
15 & 24
.
.
32 & 36 . .
3 & 4 .
13 & 14
Average pull per
yoke
Pull in pounds for each yoke
(Average of 15 observations)
Weight
in lb.
1,515
1,795
1,455
1,625
1,425
..
1
812
919
872
923
833
872
2
847
899
902
953
752
861
3
885
890
908
919
791
879
4
815
945
920
885
775
868
5
622
688
737
824
735
721
6
841
909
926
800
797
854
7
775
892
857
836
768
826
8
775
911
924
894
767
853
9
810
884
882
875
760
842
10
808
931
870
857
716
836
11
804
931
898
873
845
870
12
799
882
889
837
769
835
13
788
879
877
880
771
839
14
739
898
893
910
806
849
15
791
913
901
881
773
852
16
823
856
847
859
779
852
17
745
814
805
809
737
782
Aver-
age
793
885
877
866
775
..