WINETASTER ON 03/04/02 WITH 7 JUDGES AND 7 WINES BASED ON RANKS, IDENT=N Copyright (c) 1995-2002 Richard E. Quandt
FLIGHT 1: Number of Judges = 7 Number of Wines = 7
Identification of the Wine: The judges' overall ranking:
Wine A is Volnay Santenots ?? ........ 1st place Wine B is Clos de la Boudriau ?? ........ 6th place Wine C is Pommard Clos de la Platiere '62 ........ 5th place Wine D is Chambolle Musigny Grivelet '62 ........ 7th place Wine E is Nuits Saint Georges Michelot '64 ........ 2nd place Wine F is Gevrey Chambertin Combe aux Moines tied for 3rd place Wine G is Gevrey Chambertin Piat '66 tied for 3rd place
The Judges's Rankings
Judge Wine -> A B C D E F G Burt 5. 6. 3. 7. 1. 2. 4. John 2. 1. 7. 6. 5. 4. 3. Bob 1. 6. 3. 7. 4. 5. 2. Frank 1. 7. 5. 6. 2. 3. 4. Grant 1. 6. 3. 7. 4. 5. 2. Orley 2. 6. 1. 7. 5. 3. 4. Dick 4. 6. 3. 7. 1. 2. 5.
Table of Votes Against Wine -> A B C D E F G
Group Ranking -> 1 6 5 7 2 3 3 Votes Against -> 16 38 25 47 22 24 24
( 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 = 0.4971
The probability that random chance could be responsible for this correlation is quite small, 0.0019. 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 Frank 0.7783 Grant 0.7027 Bob 0.7027 Orley 0.5000 Dick 0.4505 Burt 0.4144 John 0.0000
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 A is Volnay Santenots ?? --------------------------------------------------- 2. ........ 2nd place Wine E is Nuits Saint Georges Michelot '64 3. tied for 3rd place Wine F is Gevrey Chambertin Combe aux Moines 4. tied for 3rd place Wine G is Gevrey Chambertin Piat '66 5. ........ 5th place Wine C is Pommard Clos de la Platiere '62 --------------------------------------------------- 6. ........ 6th place Wine B is Clos de la Boudriau ?? 7. ........ 7th place Wine D is Chambolle Musigny Grivelet '62 We now test whether the ranksums AS A WHOLE provide a significant ordering. The Friedman Chi-square value is 20.8776. The probability that this could happen by chance is 0.0019 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 Burt John Bob Burt 1.000 -0.286 0.321 John -0.286 1.000 0.179 Bob 0.321 0.179 1.000 Frank 0.571 0.071 0.679 Grant 0.321 0.179 1.000 Orley 0.464 -0.143 0.750 Dick 0.964 -0.250 0.357 Frank Grant Orley Burt 0.571 0.321 0.464 John 0.071 0.179 -0.143 Bob 0.679 1.000 0.750 Frank 1.000 0.679 0.500 Grant 0.679 1.000 0.750 Orley 0.500 0.750 1.000 Dick 0.679 0.357 0.536 Dick Burt 0.964 John -0.250 Bob 0.357 Frank 0.679 Grant 0.357 Orley 0.536 Dick 1.000 Pairwise correlations in descending order 1.000 Bob and Grant Significantly positive 0.964 Burt and Dick Significantly positive 0.750 Bob and Orley Significantly positive 0.750 Grant and Orley Significantly positive 0.679 Bob and Frank Not significant 0.679 Frank and Grant Not significant 0.679 Frank and Dick Not significant 0.571 Burt and Frank Not significant 0.536 Orley and Dick Not significant 0.500 Frank and Orley Not significant 0.464 Burt and Orley Not significant 0.357 Grant and Dick Not significant 0.357 Bob and Dick Not significant 0.321 Burt and Bob Not significant 0.321 Burt and Grant Not significant 0.179 John and Bob Not significant 0.179 John and Grant Not significant 0.071 John and Frank Not significant -0.143 John and Orley Not significant -0.250 John and Dick Not significant -0.286 Burt and John Not significant
COMMENT: There are three facts we can all agree on (1) These wines were part of a large purchase from a widow, whose husband enjoyed buying wine but not drinking it; (2) We opened 15 bottles to find 7 that were not oxidized badly; (3) However, when the wines managed to survive our initial scrutiny all agreed they were quite delicious --- except for those 2 that were slightly oxidized. We also had as part of the same cellar a 1962 Martin Ray pinot noir. This wine, which was not oxidized, was so acidic as to be unpleasant at 40 years of age. This tasting conclusively proves the old saying: "there are no old wines just old bottles." Frank disagrees with this assessment and feels that we did have some bad wines today.
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