WINETASTER ON 04/21/03 WITH 8 JUDGES AND 8 WINES BASED ON RANKS, IDENT=N Copyright (c) 1995-2003 Richard E. Quandt, V. 1.65
FLIGHT 1: Number of Judges = 8 Number of Wines = 8
Identification of the Wine: The judges' overall ranking:
Wine A is Greenhough 2000 Hope Vineyard New Zealand ........ 6th place Wine B is Spy Valley 2001 Marlborough New Zealand ........ 5th place Wine C is David Bruce 2000 Russian River California ........ 1st place Wine D is Hamilton Russell 1998 South Africa ........ 2nd place Wine E is Margrain 2001 Martinborough New Zealand ........ 8th place Wine F is Nuits Saint Georges 1999 France ........ 7th place Wine G is Mt. Difficulty 2000 Otego New Zealand ........ 3rd place Wine H is King Estate 1999 Oregon ........ 4th place
The Judges's Rankings
Judge Wine -> A B C D E F G H Jim 6. 3. 5. 7. 8. 4. 1. 2. Cate 6. 2. 1. 7. 8. 3. 4. 5. Frank 6. 7. 2. 1. 4. 8. 3. 5. Burt 8. 7. 2. 1. 6. 3. 4. 5. Orley 5. 3. 2. 1. 8. 7. 4. 6. Ed 7. 4. 1. 5. 6. 8. 2. 3. Grant 5. 1. 4. 2. 8. 7. 6. 3. Dick 1. 5. 3. 4. 7. 8. 6. 2.
Table of Votes Against Wine -> A B C D E F G H
Group Ranking -> 6 5 1 2 8 7 3 4 Votes Against -> 44 32 20 28 55 48 30 31
( 8 is the best possible, 64 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 = 0.3594
The probability that random chance could be responsible for this correlation is quite small, 0.0053. 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 Correlation Price Ed 0.7563 -0.1905 Orley 0.6190 0.4048 Grant 0.4762 0.3095 Cate 0.3713 0.1190 Frank 0.2635 -0.0714 Jim 0.2196 -0.4762 Burt 0.1796 -0.3333 Dick 0.1677 0.3571
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 C is David Bruce 2000 Russian River Cal --------------------------------------------------- 2. ........ 2nd place Wine D is Hamilton Russell 1998 South Africa 3. ........ 3rd place Wine G is Mt. Difficulty 2000 Otego New Zeal 4. ........ 4th place Wine H is King Estate 1999 Oregon 5. ........ 5th place Wine B is Spy Valley 2001 Marlborough New Ze 6. ........ 6th place Wine A is Greenhough 2000 Hope Vineyard New --------------------------------------------------- 7. ........ 7th place Wine F is Nuits Saint Georges 1999 France 8. ........ 8th place Wine E is Margrain 2001 Martinborough New Ze We now test whether the ranksums AS A WHOLE provide a significant ordering. The Friedman Chi-square value is 20.1250. The probability that this could happen by chance is 0.0053
We now test whether the group ranking of wines is correlated with the prices of the wines. The rank correlation between them is 0.0000. At the 10% level of significance this would have to exceed the critical value of 0.5240 to be significant.
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 Jim Cate Frank Jim 1.000 0.571 -0.262 Cate 0.571 1.000 -0.238 Frank -0.262 -0.238 1.000 Burt -0.048 0.167 0.595 Orley 0.048 0.333 0.571 Ed 0.476 0.452 0.571 Grant 0.214 0.286 0.143 Dick 0.000 -0.024 0.214 Burt Orley Ed Jim -0.048 0.048 0.476 Cate 0.167 0.333 0.452 Frank 0.595 0.571 0.571 Burt 1.000 0.452 0.286 Orley 0.452 1.000 0.524 Ed 0.286 0.524 1.000 Grant 0.071 0.738 0.381 Dick -0.214 0.381 0.286 Grant Dick Jim 0.214 0.000 Cate 0.286 -0.024 Frank 0.143 0.214 Burt 0.071 -0.214 Orley 0.738 0.381 Ed 0.381 0.286 Grant 1.000 0.524 Dick 0.524 1.000 Pairwise correlations in descending order 0.738 Orley and Grant Significantly positive 0.595 Frank and Burt Not significant 0.571 Frank and Ed Not significant 0.571 Jim and Cate Not significant 0.571 Frank and Orley Not significant 0.524 Orley and Ed Not significant 0.524 Grant and Dick Not significant 0.476 Jim and Ed Not significant 0.452 Cate and Ed Not significant 0.452 Burt and Orley Not significant 0.381 Ed and Grant Not significant 0.381 Orley and Dick Not significant 0.333 Cate and Orley Not significant 0.286 Burt and Ed Not significant 0.286 Ed and Dick Not significant 0.286 Cate and Grant Not significant 0.214 Frank and Dick Not significant 0.214 Jim and Grant Not significant 0.167 Cate and Burt Not significant 0.143 Frank and Grant Not significant 0.071 Burt and Grant Not significant 0.048 Jim and Orley Not significant 0.000 Jim and Dick Not significant -0.024 Cate and Dick Not significant -0.048 Jim and Burt Not significant -0.214 Burt and Dick Not significant -0.238 Cate and Frank Not significant -0.262 Jim and Frank Not significant
COMMENT: We all agreed that the wines were well-made and were drinkable. They all cost all in the same ball park. Almost all had the typically spicy nose earthy terroir. We had with us the marketer of three of the wines, and she able to correctly select two of the three---both of which were from New Zealand. The Greenhough is a bit green, slightly hot and will age well The David Bruce, the only California Pinot, was also the only wine with vanilla, oaky notes.
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