Description Usage Details Source Examples
A gear (cog wheel) with seven teeth is taken out of service and teeth examined for wear. Only adjacent pairs of teeth may be compared, but any given pair may be compared by a number of people, each of whom indicates which tooth they believe to be more worn.
The dataset is of the form of a seven-by-seven matrix, one column for
each tooth. Each row consists of precisely two non-NA
entries,
say in columns A and B. The entries indicate the number of times an
observer “prefers” (that is, judges to be more worn) tooth A and
tooth B.
The board has a single degree of freedom.
1 |
The null hypothesis is that there exist p_1,...,p_ 7 with sum(p_i)=1 such that the probability of preferring tooth i to tooth j is p_i/(p_i+p_j). Alternative hypotheses might be that the comparison has some sort of handedness in the sense that the clockwise tooth might be preferred more frequently than might be expected by chance.
Data kindly supplied by A. G. S. Hankin
1 2 3 4 | data(gear)
is.1dof(gear)
aylmer.test(gear)
aylmer.test(gear,alternative="less")
|
Loading required package: Brobdingnag
Attaching package: 'Brobdingnag'
The following objects are masked from 'package:base':
max, min, prod, range, sum
[1] TRUE
Aylmer test for count data
data: gear
p-value = 0.05094
alternative hypothesis: two.sided
Aylmer test for count data
data: gear
p-value = 6.651e-05
alternative hypothesis: less
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