STUDIES ON THE DETERMINATION OF DIGESTIBILITY COEFFICIENTS: 97
A study of these figures will show that the comparatively low standard devia-
tion under the calculation basis of 1 lb. and 3 lb. combinations (a reference to
which has already been made) have been correspondingly reflected in
a lower number of required replications. For a better comparison they are
reproduced in the following table :—
TABLE V
(1 lb. and 3 lb. basis of calculation.)
|
Paddy straw |
Linseed cake |
||||||||
|
Standard |
Number of replications |
Standard |
Number of replications |
||||||
|
5% |
10% |
15% |
5% |
10% |
15% |
||||
|
Dry matter .... |
8.515 |
3 |
... |
... |
19.300 |
15 |
4 |
2 |
|
|
Organic matter .... |
8.260 |
3 |
... |
... |
22.499 |
21 |
6 |
3 |
|
|
Crude protein .... |
32.155 |
42 |
11 |
5 |
5.589 |
2 |
... |
... |
|
|
Ether Extract .... |
25.086 |
26 |
7 |
3 |
6.110 |
2 |
... |
... |
|
|
Crude fibre .... |
8.005 |
3 |
... |
... |
487.24 |
? |
? |
? |
|
|
Nitrogen-free extract... |
7.790 |
3 |
... |
... |
23.179 |
22 |
6 |
3 |
|
As already stated, these results have been worked out from a rather limited
number of requisite types of data. Nevertheless, they serve as actual illustrations
of the possible order of uniformity or otherwise and the trend and possibility of the
reduction in errors by means of a reasonable number of replications. We note
here that with respect to four only of six components of paddy straw, viz., dry
matter, organic matter, crude fibre and nitrogen-free extract, not more than
three replications would be necessary to keep the error within 5%. But crude
protein and ether extract appear to be liable to greater fluctuations, in consequence
of which even an error of 10% seems to be beset with practical difficulties, as
even then it would require as many as 11 replications (7 for ether extract and
11 for crude protein). In fact in these two cases it may ordinarily be a more feasi-
ble course to be satisfied with an error as high as 15%, for it is only then that the
replications can be kept within the moderate limit of 3 to 5.
In the case of linseed cake, crude protein and ether extract are the only
two components whose errors are concomitant with low replications. For the
values with 1 and 3 lb. basis of calculation even a replication of 2 is enough to
keep the error within 5%, but in respect of other components the position is
different. As many as 4 to 6 replications would be necessary in the case of dry
matter, organic matter and nitrogen-free extract to keep the error within 10%,
whereas, even this is not sufficient with respect to crude fibre,