In Zea mays it is as 100 to 84, and in the
others it ranges between 100 to 76 and 100 to 86."
"The determination of the variability (measured by what is technically
called the 'probable error') is a problem of more delicacy than that of
determining the means, and I doubt, after making many trials, whether it
is possible to derive useful conclusions from these few observations. We
ought to have measurements of at least fifty plants in each case, in
order to be in a position to deduce fair results. One fact, however,
bearing on variability, is very evident in most cases, though not in Zea
mays, namely, that the self-fertilised plants include the larger number
of exceptionally small specimens, while the crossed are more generally
full grown."
"Those groups of cases in which measurements have been made of a few of
the tallest plants that grew in rows, each of which contained a
multitude of plants, show very clearly that the crossed plants exceed
the self-fertilised in height, but they do not tell by inference
anything about their respective mean values. If it should happen that a
series is known to follow the law of error or any other law, and if the
number of individuals in the series is known, it would be always
possible to reconstruct the whole series when a fragment of it has been
given. But I find no such method to be applicable in the present case.
The doubt as to the number of plants in each row is of minor importance;
the real difficulty lies in our ignorance of the precise law followed by
the series.
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