WINETASTER ON 05/03/99 WITH 5 JUDGES AND 7 WINES BASED ON RANKS, IDENT=N Copyright (c) 1995-99 Richard E. Quandt


FLIGHT 1: Number of Judges = 5 Number of Wines = 7
Identification of the Wine: The judges' overall ranking:
Wine A is Ch. Cheval Blanc 1990 ........ 2nd place Wine B is Ch. Leoville Barton 1990 ........ 7th place Wine C is Ch. Haut Brion 1990 tied for 3rd place Wine D is Ch. Meyney 1990 tied for 3rd place Wine E is Ch. Lafite Rothschild 1990 ........ 5th place Wine F is Ch. Bourgneuf 1990 ........ 6th place Wine G is Ch. Margaux 1990 ........ 1st place
The Judges's Rankings
Judge Wine -> A B C D E F G Grant 1. 2. 7. 3. 6. 5. 4. John 5. 7. 4. 6. 2. 1. 3. Burt 6. 7. 1. 2. 5. 4. 3. Bob 3. 4. 7. 2. 5. 6. 1. Dick 4. 5. 1. 7. 3. 6. 2.
Table of Votes Against Wine -> A B C D E F G
Group Ranking -> 2 7 3 3 5 6 1 Votes Against -> 19 25 20 20 21 22 13
( 5 is the best possible, 35 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 = 0.1143

The probability that random chance could be responsible for this correlation is rather large, 0.7534. 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 Bob -0.0371 Dick -0.1429 Burt -0.3706 John -0.4144 Grant -0.7207

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 G is Ch. Margaux 1990 2. ........ 2nd place Wine A is Ch. Cheval Blanc 1990 3. tied for 3rd place Wine C is Ch. Haut Brion 1990 4. tied for 3rd place Wine D is Ch. Meyney 1990 5. ........ 5th place Wine E is Ch. Lafite Rothschild 1990 6. ........ 6th place Wine F is Ch. Bourgneuf 1990 7. ........ 7th place Wine B is Ch. Leoville Barton 1990 We now test whether the ranksums AS A WHOLE provide a significant ordering. The Friedman Chi-square value is 3.4286. The probability that this could happen by chance is 0.7534 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 Grant John Burt Grant 1.000 -0.643 -0.607 John -0.643 1.000 0.214 Burt -0.607 0.214 1.000 Bob 0.643 -0.357 -0.107 Dick -0.500 0.250 0.250 Bob Dick Grant 0.643 -0.500 John -0.357 0.250 Burt -0.107 0.250 Bob 1.000 -0.214 Dick -0.214 1.000 Pairwise correlations in descending order 0.643 Grant and Bob Not significant 0.250 John and Dick Not significant 0.250 Burt and Dick Not significant 0.214 John and Burt Not significant -0.107 Burt and Bob Not significant -0.214 Bob and Dick Not significant -0.357 John and Bob Not significant -0.500 Grant and Dick Not significant -0.607 Grant and Burt Not significant -0.643 Grant and John Not significant




COMMENT: This was an extraordinarily wonderful wine tasting and the lack of agreement indicates that these were all wonderful wines and 1990 is a wonderful vintage, says Burt. Bob adds athat he agrees with Burt, these are amazing wines, perhaps the best of the century. Differentiation is more noise than anything else. John says that these wines were all so good that the dispersion is unusually high, as expected. Grant says that the wines have great fruit.
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