WINETASTER ON 03/01/99 WITH 6 JUDGES AND 6 WINES BASED ON RANKS, IDENT=N Copyright (c) 1995-98 Richard E. Quandt
FLIGHT 1: Number of Judges = 6 Number of Wines = 6
Identification of the Wine: The judges' overall ranking:
Wine A is Plaisir de Merle Cabernet 1995 ........ 2nd place Wine B is Le Bonheur Cabernet 1995 ........ 1st place Wine C is Hartenberg Shiraz 1995 ........ 6th place Wine D is Kaapzicht Pinotage Reserve 1997 tied for 3rd place Wine E is Nederburg Private Bin R 103 1989 ........ 5th place Wine F is Thelema Cabernet 1995 tied for 3rd place
The Judges's Rankings
Judge Wine -> A B C D E F Orley 2. 1. 6. 3. 5. 4. Bob 6. 1. 5. 2. 4. 3. John 2. 4. 5. 6. 1. 3. Ed 3. 1. 6. 4. 5. 2. Burt 5. 1. 4. 2. 3. 6. Dick 3. 1. 2. 5. 6. 4.
Table of Votes Against Wine -> A B C D E F
Group Ranking -> 2 1 6 3 5 3 Votes Against -> 21 9 28 22 24 22
( 6 is the best possible, 36 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 = 0.3238
The probability that random chance could be responsible for this correlation is quite small, 0.0837. 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 Orley 0.6983 Ed 0.6377 Bob 0.3189 Burt 0.1160 Dick 0.0911 John -0.4119
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 Le Bonheur Carbernet 1995 --------------------------------------------------- 2. ........ 2nd place Wine A is Plaisir de Merle Cabernet 1995 3. tied for 3rd place Wine F is Thelema Cabernet 1995 4. tied for 3rd place Wine D is Kaapzicht Pinotage Reserve 1997 5. ........ 5th place Wine E is Nederburg Private Bin R 103 1989 --------------------------------------------------- 6. ........ 6th place Wine C is Hartenberg Shiraz 1995 We now test whether the ranksums AS A WHOLE provide a significant ordering. The Friedman Chi-square value is 9.7143. The probability that this could happen by chance is 0.0837 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 0.89 for significance at the 0.05 level and must exceed 0.83 for significance at the 0.1 level Orley Bob John Orley 1.000 0.429 -0.029 Bob 0.429 1.000 -0.429 John -0.029 -0.429 1.000 Ed 0.829 0.543 0.086 Burt 0.371 0.657 -0.371 Dick 0.371 0.086 -0.314 Ed Burt Dick Orley 0.829 0.371 0.371 Bob 0.543 0.657 0.086 John 0.086 -0.371 -0.314 Ed 1.000 0.086 0.371 Burt 0.086 1.000 0.143 Dick 0.371 0.143 1.000 Pairwise correlations in descending order 0.829 Orley and Ed Not significant 0.657 Bob and Burt Not significant 0.543 Bob and Ed Not significant 0.429 Orley and Bob Not significant 0.371 Orley and Dick Not significant 0.371 Orley and Burt Not significant 0.371 Ed and Dick Not significant 0.143 Burt and Dick Not significant 0.086 Ed and Burt Not significant 0.086 John and Ed Not significant 0.086 Bob and Dick Not significant -0.029 Orley and John Not significant -0.314 John and Dick Not significant -0.371 John and Burt Not significant -0.429 Bob and John Not significant
COMMENT:
These wines were much better than anyone at the table expected. The wines to the best of our knowledge are not widely available in the United States with the exception of the Thelema. These wines appeared to differ from one another to a greater degree than representative bottles in our tastings. The prices ranged from $5 for A to $15 for E and F. E had a noticeably sweeter fruit character, but not because of sugar. The wines are drinking noticeably well now, in spite of their youth. The wines were brought directly from South Africa, and prices may be higher if they have to go through the three-tier distribution system.