WINETASTER ON 05/07/12 WITH 7 JUDGES AND 7 WINES BASED ON RANKS, IDENT=N
Copyright (c) 1995-2012 Richard E. Quandt, V. 1.65
Number of Judges = 7
Number of Wines = 7
Identification of the Wine: The judges' overall ranking:
Wine A is Chave Hermitage 1989 ........ 2nd place
Wine B is Chave Hermitage 1985 ........ 4th place
Wine C is Chave Hermitage 1990 ........ 1st place
Wine D is Chave Hermitage 1988 ........ 3rd place
Wine E is Chave Hermitage 1998 tied for 5th place
Wine F is Chave Hermitage 2000 ........ 7th place
Wine G is Chave Hermitage 1994 tied for 5th place
The Judges's Rankings
Judge Wine -> A B C D E F G
Mike 3. 5. 2. 1. 6. 7. 4.
Orley 6. 7. 1. 3. 2. 4. 5.
Ed 3. 5. 7. 1. 6. 2. 4.
Bob 2. 3. 7. 5. 4. 6. 1.
Zaki 3. 1. 2. 4. 6. 7. 5.
Robby 3. 7. 1. 5. 4. 2. 6.
Dick 3. 2. 1. 6. 4. 5. 7.
Table of Votes Against
Wine -> A B C D E F G
Group Ranking -> 2 4 1 3 5 7 5
Votes Against -> 23 30 21 25 32 33 32
( 7 is the best possible, 49 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 = 0.1050
The probability that random chance could be responsible for this correlation
is rather large, 0.6216. Most analysts would say that unless this
probability is less than 0.1, the judges' preferences are not strongly
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
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
1. ........ 1st place Wine C is Chave Hermitage 1990
2. ........ 2nd place Wine A is Chave Hermitage 1989
3. ........ 3rd place Wine D is Chave Hermitage 1988
4. ........ 4th place Wine B is Chave Hermitage 1985
5. tied for 5th place Wine E is Chave Hermitage 1998
6. tied for 5th place Wine G is Chave Hermitage 1994
7. ........ 7th place Wine F is Chave Hermitage 2000
We now test whether the ranksums AS A WHOLE provide a significant ordering.
The Friedman Chi-square value is 4.4082. The probability that this could
happen by chance is 0.6216
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 0.79 for significance at the 0.05
level and must exceed 0.71 for significance at the 0.1 level
Mike Orley Ed
Mike 1.000 0.214 0.107
Orley 0.214 1.000 -0.321
Ed 0.107 -0.321 1.000
Bob -0.071 -0.714 0.107
Zaki 0.536 -0.286 -0.357
Robby 0.036 0.607 -0.143
Dick 0.071 0.071 -0.643
Bob Zaki Robby
Mike -0.071 0.536 0.036
Orley -0.714 -0.286 0.607
Ed 0.107 -0.357 -0.143
Bob 1.000 0.071 -0.679
Zaki 0.071 1.000 -0.214
Robby -0.679 -0.214 1.000
Dick -0.357 0.679 0.357
Pairwise correlations in descending order
0.679 Zaki and Dick Not significant
0.607 Orley and Robby Not significant
0.536 Mike and Zaki Not significant
0.357 Robby and Dick Not significant
0.214 Mike and Orley Not significant
0.107 Ed and Bob Not significant
0.107 Mike and Ed Not significant
0.071 Mike and Dick Not significant
0.071 Orley and Dick Not significant
0.071 Bob and Zaki Not significant
0.036 Mike and Robby Not significant
-0.071 Mike and Bob Not significant
-0.143 Ed and Robby Not significant
-0.214 Zaki and Robby Not significant
-0.286 Orley and Zaki Not significant
-0.321 Orley and Ed Not significant
-0.357 Bob and Dick Not significant
-0.357 Ed and Zaki Not significant
-0.643 Ed and Dick Not significant
-0.679 Bob and Robby Not significant
-0.714 Orley and Bob Significantly negative
Much to our delight, our host poured the mature, delicious 1997 and 1999 Mayacamas Chardonnay's
as we gathered before this wine tasting.
Overall, this was a fantastic tasting of consistent and typical wines of
the great Hermitage Appelation. There is a great consistency of style
across the vintages that is typical of the appelation and the house.
Several tasters noted that as the tasting was going on that they changed their
ranking an unusual number of times.
There was wide agrement that these wines have noticeable acidity and would
be excellent with a meal.
These wines are all very expensive, averaging about $225-$250/bottle.
We conclude that while there may be preference differences among the judges,
these were such fantastic wines that they were all judged to be excellent.
One taster, Bob, noted that he was rather negative in his evaluation of wine C,
the 1990, but that might be explained by the fact that his glass was filled
from the bottom of the bottle and thus had unusual amount of dregs in it. We there-
fore reran the computer programwithou Bob. The new Kendall W turned out to be
0.2063, overall still not significant (the probability that it could have
occurred by chance now being 0.2830, quite a bit lower than the 0.6216 we had before).
However, wine C now turns out to be significantly high in quality. Of course, we don't
mean this literally, since once you have computed statistics from the data, you really can't
just omit some of the data and recompute, but it is an interesting exercise nevertheless.
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