WINETASTER ON 02/05/01 WITH 4 JUDGES AND 4 WINES BASED ON RANKS, IDENT=N
Copyright (c) 1995-2001 Richard E. Quandt
FLIGHT 1:
Number of Judges = 4
Number of Wines = 4
Identification of the Wine: The judges' overall ranking:
Wine A is Ch. Margaux 1959 ........ 4th place
Wine B is Ch. Margaux 1966 ........ 1st place
Wine C is Ch. Haut Brion 1959 ........ 2nd place
Wine D is Ch. Latour 1959 ........ 3rd place
The Judges's Rankings
Judge Wine -> A B C D
Orley 3. 1. 2. 4.
John 4. 1. 2. 3.
Burt 4. 1. 2. 3.
Grant 4. 1. 2. 3.
Table of Votes Against
Wine -> A B C D
Group Ranking -> 4 1 2 3
Votes Against -> 15 4 8 13
( 4 is the best possible, 16 is the worst)
Here is a measure of the correlation in the preferences of the judges which
ranges between 1.0 (perfect correlation) and 0.0 (no correlation):
W = 0.9250
The probability that random chance could be responsible for this correlation
is quite small, 0.0112. Most analysts would say that unless this
probability is less than 0.1, the judges' preferences are not strongly
related.
We now analyze how each taster's preferences are correlated with the group
preference. A correlation of 1.0 means that the taster's preferences are a
perfect predictor of the group's preferences. A 0.0 means no correlation,
while a -1.0 means that the taster has the reverse ranking of the group.
This is measured by the correlation R.
Correlation Between the Ranks of
Each Person With the Average Ranking of Others
Name of Person Correlation R
Burt 1.0000
John 1.0000
Grant 1.0000
Orley 0.8000
The wines were preferred by the judges in the following order. When the
preferences of the judges are strong enough to permit meaningful differentiation
among the wines, they are separated by -------------------- and are judged to be
significantly different.
1. ........ 1st place Wine B is Ch. Margaux 1966
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2. ........ 2nd place Wine C is Ch. Haut Brion 1959
3. ........ 3rd place Wine D is Ch. Latour 1959
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4. ........ 4th place Wine A is Ch. Margaux 1959
We now test whether the ranksums AS A WHOLE provide a significant ordering.
The Friedman Chi-square value is 11.1000. The probability that this could
happen by chance is 0.0112
We now undertake a more detailed examination of the pair-wise rank correla-
tions that exist between pairs of judges. First, we present a table in which you
can find the correlation for any pair of judges, by finding one of the names in the
left hand margin and the other name on top of a column. A second table arranges
these correlations in descending order and marks which is significantly positive
significantly negative, or not significant. This may allow you to find clusters
of judges whose rankings were particularly similar or particularly dissimilar.
Pairwise Rank Correlations
Correlations must exceed in absolute value 1.00 for significance at the 0.05
level and must exceed 1.00 for significance at the 0.1 level
Orley John Burt
Orley 1.000 0.800 0.800
John 0.800 1.000 1.000
Burt 0.800 1.000 1.000
Grant 0.800 1.000 1.000
Grant
Orley 0.800
John 1.000
Burt 1.000
Grant 1.000
Pairwise correlations in descending order
1.000 John and Burt Significantly positive
1.000 John and Grant Significantly positive
1.000 Burt and Grant Significantly positive
0.800 Orley and John Not significant
0.800 Orley and Burt Not significant
0.800 Orley and Grant Not significant
COMMENTS:
This event met with some serious weather problems! It turned out that we were convening during the middle of a major snow storm. Three people were unable to get over the roads, leaving us with only 4 tasters. The storm also reduced the number of wines,
as two of them did not show up either.
Of the wines the 1959 Margaux and the 1959 Latour were oxidized. There was unanimity that in this tasting the 1966 Margaux, which was still firm and in good condition, was a better wine than the 1959 Haut Brion. All the wines came from the same cellar.
This suggests that the 1959s may finally be coming toward the end of their best drinking period. In the past the 59 Haut Brion has been a magnificent wine, but here it was much lighter than most of us remember it being in the past. Perhaps it is time t
o drink up-and stop tempting fate.
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