WINETASTER ON 06/03/13 WITH 8 JUDGES AND 8 WINES BASED ON RANKS, IDENT=N Copyright (c) 1995-2013 Richard E. Quandt, V. 1.65
A Tasting of TURLEY Petite Sirahs and Zinfandels
FLIGHT 1: Number of Judges = 8 Number of Wines = 8
Identification of the Wine: The judges' overall ranking:
Wine A is Petite Sirah 1994 Aida Vineyard, Napa tied for 4th place Wine B is Zinfandel 1994 Earthquake Vineyard, Napa ........ 8th place Wine C is Zinfandel 1997 Grist Vineyard, Sonoma ........ 7th place Wine D is Zinfandel 1996 Duarte Vineyard, Contra Costa tied for 4th place Wine E is Petite Sirah 1997 Aida Vineyard, Napa tied for 2nd place Wine F is Petite Sirah 1995 Aida Vineyard, Napa tied for 2nd place Wine G is Petite Sirah 1996 Aida Vineyard, Napa ........ 1st place Wine H is Zinfandel 1995 Black Sears Vineyard, Napa tied for 4th place
The Judges's Rankings
Judge Wine -> A B C D E F G H Alexa 6. 7. 8. 4. 5. 1. 2. 3. Mike 4. 8. 6. 7. 1. 5. 3. 2. Burt 5. 7. 6. 2. 1. 4. 3. 8. Orley 6. 4. 5. 7. 1. 2. 3. 8. Zaki 5. 6. 8. 4. 2. 3. 1. 7. Bob 4. 5. 7. 8. 6. 2. 1. 3. Ed 3. 8. 7. 6. 4. 1. 2. 5. Dick3 7. 8. 1. 2. 3. 5. 6. 4.
Table of Votes Against Wine -> A B C D E F G H
Group Ranking -> 4 8 7 4 2 2 1 4 Votes Against -> 40 53 48 40 23 23 21 40
( 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 = 0.3884
The probability that random chance could be responsible for this correlation is quite small, 0.0028. 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 Zaki 0.7425 Ed 0.7186 Alexa 0.5714 Mike 0.4551 Burt 0.4524 Orley 0.4286 Bob 0.2619 Dick3 -0.3095
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 Petite Sirah 1996 2. tied for 2nd place Wine F is Petite Sirah 1995 3. tied for 2nd place Wine E is Petite Sirah 1997 --------------------------------------------------- 4. tied for 4th place Wine D is Zinfandel 1996 5. tied for 4th place Wine A is Petite Sirah 1994 6. tied for 4th place Wine H is Zinfandel 1995 --------------------------------------------------- 7. ........ 7th place Wine C is Zinfandel 1997 8. ........ 8th place Wine B is Zinfandel 1994 We now test whether the ranksums AS A WHOLE provide a significant ordering. The Friedman Chi-square value is 21.7500. The probability that this could happen by chance is 0.0028 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 Alexa Mike Burt Alexa 1.000 0.381 0.286 Mike 0.381 1.000 0.238 Burt 0.286 0.238 1.000 Orley 0.167 0.214 0.524 Zaki 0.619 0.381 0.810 Bob 0.667 0.405 -0.190 Ed 0.762 0.548 0.405 Dick3 -0.095 0.095 0.286 Orley Zaki Bob Alexa 0.167 0.619 0.667 Mike 0.214 0.381 0.405 Burt 0.524 0.810 -0.190 Orley 1.000 0.643 0.238 Zaki 0.643 1.000 0.381 Bob 0.238 0.381 1.000 Ed 0.405 0.690 0.714 Dick3 -0.143 -0.190 -0.595 Ed Dick3 Alexa 0.762 -0.095 Mike 0.548 0.095 Burt 0.405 0.286 Orley 0.405 -0.143 Zaki 0.690 -0.190 Bob 0.714 -0.595 Ed 1.000 -0.214 Dick3 -0.214 1.000 Pairwise correlations in descending order 0.810 Burt and Zaki Significantly positive 0.762 Alexa and Ed Significantly positive 0.714 Bob and Ed Significantly positive 0.690 Zaki and Ed Significantly positive 0.667 Alexa and Bob Significantly positive 0.643 Orley and Zaki Not significant 0.619 Alexa and Zaki Not significant 0.548 Mike and Ed Not significant 0.524 Burt and Orley Not significant 0.405 Mike and Bob Not significant 0.405 Orley and Ed Not significant 0.405 Burt and Ed Not significant 0.381 Zaki and Bob Not significant 0.381 Alexa and Mike Not significant 0.381 Mike and Zaki Not significant 0.286 Alexa and Burt Not significant 0.286 Burt and Dick3 Not significant 0.238 Orley and Bob Not significant 0.238 Mike and Burt Not significant 0.214 Mike and Orley Not significant 0.167 Alexa and Orley Not significant 0.095 Mike and Dick3 Not significant -0.095 Alexa and Dick3 Not significant -0.143 Orley and Dick3 Not significant -0.190 Zaki and Dick3 Not significant -0.190 Burt and Bob Not significant -0.214 Ed and Dick3 Not significant -0.595 Bob and Dick3 Not significant
COMMENT: Petite Sirah is also known as Durif; see Wikipedia and the footnotes therein. Note that we have had another tasting in which Petite Sirahs were featured (but without the Zinfandels), almost ten years ago in Report 61. The overlap in vintages between that tasting and the present one is too modest to permit an analysis of intertemporal consistency. None of us could recall another tasting in which as many as three out of eight wines were judged to be significantly good and as many as two other wines were deemed to be significantly inferior: the probability that the observed Kendall W could have occurred by chance was 0.0028, another landmark value. There was a clear preference among the tasters for the Petite Sirahs, and it was a unique tasting in that three of the Petite Sirahs were judged to be significantly good. Many thought that the Zinfandels were obviously alcoholic (2% more alcohol than the Petite Sirahs) and they did not display the fruit that the Petite Sirahs did. The average points against the four Petite Sirahs was 26.75 while the points against the four Zinfandels was 45.25. There are many people who have thought that the high alcohol Zinfandels of Turley from the 1990s would turn out to be shallow alcoholic hulls, like some weightlifters who use steroids when young. The good news is that Napa valley Petite Sirahs are underrated wines with much greater longevity and balance.
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