WINETASTER ON 03/06/00 WITH 6 JUDGES AND 8 WINES BASED ON RANKS, IDENT=N Copyright (c) 1995-2000 Richard E. Quandt
FLIGHT 1: Number of Judges = 6 Number of Wines = 8
Identification of the Wine: The judges' overall ranking:
Wine A is Hermitage La Chappelle 1994 tied for 2nd place Wine B is Hermitage Monier 1990 ........ 1st place Wine C is Hermitage La Chappelle 1989 tied for 2nd place Wine D is Saint Joseph Trollat 1994 ........ 7th place Wine E is Saint-Joseph Perret 1990 ........ 5th place Wine F is Saint-Joseph Fleury 1991 ........ 6th place Wine G is Saint-Joseph Trollat 1989 ........ 8th place Wine H is Hermitage Monier 1991 ........ 4th place
The Judges's Rankings
Judge Wine -> A B C D E F G H Bob 5. 1. 4. 8. 6. 3. 7. 2. Grant 1. 2. 3. 4. 5. 8. 7. 6. Burt 3. 1. 7. 8. 5. 2. 6. 4. Alexa 1. 5. 2. 8. 4. 7. 6. 3. John 2. 1. 3. 6. 5. 4. 8. 7. Dick 8. 3. 1. 2. 4. 6. 7. 5.
Table of Votes Against Wine -> A B C D E F G H
Group Ranking -> 2 1 2 7 5 6 8 4 Votes Against -> 20 13 20 36 29 30 41 27
( 6 is the best possible, 48 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 = 0.3862
The probability that random chance could be responsible for this correlation is quite small, 0.0232. 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 John 0.8095 Grant 0.6429 Bob 0.5952 Alexa 0.5000 Burt 0.3832 Dick 0.0359
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 Hermitage Monier 1990 --------------------------------------------------- 2. tied for 2nd place Wine A is Hermitage La Chappelle 1994 3. tied for 2nd place Wine C is Hermitage La Chappelle 1989 4. ........ 4th place Wine H is Hermitage Monier 1991 5. ........ 5th place Wine E is Saint-Joseph Perret 1990 6. ........ 6th place Wine F is Saint-Joseph Fleury 1991 --------------------------------------------------- 7. ........ 7th place Wine D is Saint Joseph Trollat 1994 8. ........ 8th place Wine G is Saint-Joseph Trollat 1989 We now test whether the ranksums AS A WHOLE provide a significant ordering. The Friedman Chi-square value is 16.2222. The probability that this could happen by chance is 0.0232 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 0.74 for significance at the 0.05 level and must exceed 0.64 for significance at the 0.1 level Bob Grant Burt Bob 1.000 0.095 0.762 Grant 0.095 1.000 0.071 Burt 0.762 0.071 1.000 Alexa 0.310 0.548 0.143 John 0.500 0.714 0.548 Dick 0.048 0.238 -0.429 Alexa John Dick Bob 0.310 0.500 0.048 Grant 0.548 0.714 0.238 Burt 0.143 0.548 -0.429 Alexa 1.000 0.381 -0.143 John 0.381 1.000 0.167 Dick -0.143 0.167 1.000 Pairwise correlations in descending order 0.762 Bob and Burt Significantly positive 0.714 Grant and John Significantly positive 0.548 Burt and John Not significant 0.548 Grant and Alexa Not significant 0.500 Bob and John Not significant 0.381 Alexa and John Not significant 0.310 Bob and Alexa Not significant 0.238 Grant and Dick Not significant 0.167 John and Dick Not significant 0.143 Burt and Alexa Not significant 0.095 Bob and Grant Not significant 0.071 Grant and Burt Not significant 0.048 Bob and Dick Not significant -0.143 Alexa and Dick Not significant -0.429 Burt and Dick Not significant
COMMENT: The wines were absolutely wonderful and it is clear that the Hermitages won the day; the sum of the votes against for the Hermitages was 80, whereas the sum was 136 for the Saint Josephs. The wines are all still quite young and continued to evolve throughout the tasting. The Hermitage 1991 was somewhat tannic. It was difficult to tell the Saint-Josephs from the Hermitages from the tasting itself but the scores tell the story.
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