WINETASTER ON 04/06/15 WITH 6 JUDGES AND 3 WINES BASED ON RANKS, IDENT=N
Copyright (c) 1995-2015 Richard E. Quandt, V. 1.65
Number of Judges = 6
Number of Wines = 3
Identification of the Wine: The judges' overall ranking:
Wine A is Lytton Springs Zinfandel 1990 ........ 1st place
Wine B is Geyserville Zinfandel 1987 tied for 2nd place
Wine C is Geyserville Zinfandel 1986 tied for 2nd place
The Judges's Rankings
Judge Wine -> A B C
Ed 1. 2. 3.
Burt 1. 3. 2.
Orley 3. 1. 2.
Zaki 1. 2. 3.
Bob 1. 3. 2.
Dick 1. 3. 2.
Table of Votes Against
Wine -> A B C
Group Ranking -> 1 2 2
Votes Against -> 8 14 14
( 6 is the best possible, 18 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 = 0.3333
The probability that random chance could be responsible for this correlation
is rather large, 0.1353. Most analysts would say that unless this
probability is less than 0.1, the judges' preferences are not strongly
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
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
1. ........ 1st place Wine A is Lytton Springs Zinfandel 1990
2. tied for 2nd place Wine B is Geyserville Zinfandel 1987
3. tied for 2nd place Wine C is Geyserville Zinfandel 1986
We now test whether the ranksums AS A WHOLE provide a significant ordering.
The Friedman Chi-square value is 4.0000. The probability that this could
happen by chance is 0.1353
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 1.00 for significance at the 0.05
level and must exceed 1.00 for significance at the 0.1 level
Ed Burt Orley
Ed 1.000 0.500 -0.500
Burt 0.500 1.000 -1.000
Orley -0.500 -1.000 1.000
Zaki 1.000 0.500 -0.500
Bob 0.500 1.000 -1.000
Dick 0.500 1.000 -1.000
Zaki Bob Dick
Ed 1.000 0.500 0.500
Burt 0.500 1.000 1.000
Orley -0.500 -1.000 -1.000
Zaki 1.000 0.500 0.500
Bob 0.500 1.000 1.000
Dick 0.500 1.000 1.000
Pairwise correlations in descending order
1.000 Burt and Bob Significantly positive
1.000 Burt and Dick Significantly positive
1.000 Ed and Zaki Significantly positive
1.000 Bob and Dick Significantly positive
0.500 Ed and Bob Not significant
0.500 Zaki and Bob Not significant
0.500 Burt and Zaki Not significant
0.500 Ed and Dick Not significant
0.500 Ed and Burt Not significant
0.500 Zaki and Dick Not significant
-0.500 Orley and Zaki Not significant
-0.500 Ed and Orley Not significant
-1.000 Burt and Orley Significantly negative
-1.000 Orley and Bob Significantly negative
-1.000 Orley and Dick Significantly negative
Just three wines, two (1986 and 1987) are from the original Trentadue
Vineyard in the Geyserville appellation in Sonoma — these vines were torn out
after the 1987 harvest and the vineyard was leased to another winery. These two
wines were released in Ridge's ATP program, and they will neveer be reproduced.
The 1990 was from the Lytton Springs appellation, Norton and Valley Vista vineyards.
Can we tell the Geyserville wines from the Lytton Springs wines?
Paul Draper, still the wine maker at Ridge, made these wines. His wine making
follows the Bordeaux recipe, pumpimg over the cap, barrel aging/ Many people think
these are one of the few examples of a wine unique to Calufornia.
It was noticeable to one member of the group that, in strong contrast
to his previous experience of Califconia Zinfandels, these three wines
had a striking similarity to good Bordeaux.
Several tasters were surprised that the youngest wine, i.e. the 1990,
appeared to be the most mature and tannin-free bottle.
If we had tasted 1986 in isolation, we would never have thought that it
was a Zinfandel that was 30 years old. With so few wines and relatively few
tasters, we did not really expect significant results in the rankings, but
the 1990 turned out to be significantly superior.
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