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EFFECT OF MUSCULAR EXERCISE ON SEMEN [Vol. XXII, Part II,
the more precise estimate. Since the error of the mean is dependent on the error
M. S., the least value of the error M. S., would also correspond to the best estimate.
In Table V are shown the 3 groups of error M. S's found for each criterion studied.
Their examination show the existence of a clear 'trend'.* Thus the error
M. S. values progressively decreased with the increase in the number of observations
averaged—the highest value being given by A where a single observation was used
and the least by C where all the four observations were utilised. This suggests that
when more than one observation within a period is available, it is undesirable to
carry out analysis using only a single observation. This will besides, obviate the
necessity of adopting the complicated technique of analysis of incomplete observa-
tions, without much risk of any wide deviation from exactitude, if the numbers
of observations per period are sufficiently numerous. The straight forward course
in such cases would appear to be to take all the observations within a period as done
by Cochran, Autrey and Cannon [1941] and Branton, Bratton and Salisbury [1947]
for getting more precise results. We have adopted this precedure in analysing the
data in this and subsequent experiment and the results discussed are on the basis of
averages of all observations within a period. The analysis of variance conducted
is given in Table V. From Tables III and V it will be seen that:
(i) Volume. In both ejaculates, bulls in the 'no-exercise' groups produced on
an average larger volumes than those in the 'exercise' group. The overall mean
for the former was 1.70 c.c. as compared to 1.54 c.c. of the latter. The difference
was not statistically, significant.
(ii) Initial motility. In the first ejaculate, the mean motility rating was slightly
higher for the exercised group than the non-exercised one; while it was the other
way about in the second ejaculate. The overall means for the exercised and non-
exercised animals were 3.33 and 3.19 respectively. The differences between treat-
ments and ejaculates approached the 5 per cent level of significance, while the inter-
action treatment ejaculates was highly significant.
(iii) Sperm concentration. In both ejaculates, the sperm concentration was
higher in the exercised than in the non-exercised bulls. The overall means for the
exercised and non-exercised lots were 835 and 744 millions per c.c. respectively.
The difference approached the 5 per cent level of significance.
(iv) Percent of abnormal sperm. The exercised bulls had a lesser percentage
of abnormal sperm than the non-exercised bulls in both the ejaculates. The overall
respective means were 5.37 per cent and 6.10 per cent. The difference was signifi-
cant at 5 per cent level.
(v) Reaction time. In both ejaculates, on an average the non-exercised bulls
took a longer time than the exercised ones for giving the ejaculates, the overall
means being 75 and 92 seconds respectively. The difference was not statistically
significant.
* In these cases in which observations were incomplete, the M. S. for procedure A has been
omitted as involving complications.