WINETASTER ON 11/02/09 WITH 7 JUDGES AND 7 WINES BASED ON RANKS, IDENT=N Copyright (c) 1995-2009 Richard E. Quandt, V. 1.65
FLIGHT 1: Number of Judges = 7 Number of Wines = 7
Identification of the Wine: The judges' overall ranking:
Wine A is Sette Ponti Oreno 2003 ........ 5th place Wine B is Lamborghini Campoleone 2001 ........ 6th place Wine C is Brunello di Montalcino Castelgiocondo Frescobaldi 2001 tied for 1st place Wine D is Moris Farms Avvoltore 2003 tied for 1st place Wine E is La Brancaia Ilatria 2003 tied for 1st place Wine F is Ruleja, Barbera di Asti 1999 ........ 7th place Wine G is Elio Grasso Barolo Gavarini Chiniera 2004 ........ 4th place
The Judges's Rankings
Judge Wine -> A B C D E F G John 4. 7. 5. 1. 2. 3. 6. Mike 7. 4. 6. 1. 2. 5. 3. Nick 7. 1. 2. 3. 4. 6. 5. Dick 4. 6. 2. 3. 1. 7. 5. Bob 1. 7. 3. 6. 2. 5. 4. Ed 2. 3. 1. 4. 6. 7. 5. Richard 6. 7. 2. 3. 4. 5. 1.
Table of Votes Against Wine -> A B C D E F G
Group Ranking -> 5 6 1 1 1 7 4 Votes Against -> 31 35 21 21 21 38 29
( 7 is the best possible, 49 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 = 0.2230
The probability that random chance could be responsible for this correlation is rather large, 0.1539. 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 Dick 0.8214 Richard 0.2523 John 0.2500 Mike 0.1071 Nick 0.0360 Bob -0.0714 Ed -0.0714
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. tied for 1st place Wine D is Moris Farms Avvoltore 2003 2. tied for 1st place Wine E is La Brancaia Ilatria 2003 3. tied for 1st place Wine C is Brunello di Montalcino Frescobaldi 2001 4. ........ 4th place Wine G is Elio Grasso Barolo Gavarini 2004 5. ........ 5th place Wine A is Sette Ponti Oreno 2003 6. ........ 6th place Wine B is Lamborghini Campoleone 2001 --------------------------------------------------- 7. ........ 7th place Wine F is Ruleja, Barbera di Asti 1999 We now test whether the ranksums AS A WHOLE provide a significant ordering. The Friedman Chi-square value is 9.3673. The probability that this could happen by chance is 0.1539 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 John Mike Nick John 1.000 0.429 -0.286 Mike 0.429 1.000 0.321 Nick -0.286 0.321 1.000 Dick 0.429 0.250 0.214 Bob 0.179 -0.429 -0.571 Ed -0.393 -0.500 0.357 Richard 0.107 0.321 0.036 Dick Bob Ed John 0.429 0.179 -0.393 Mike 0.250 -0.429 -0.500 Nick 0.214 -0.571 0.357 Dick 1.000 0.536 0.286 Bob 0.536 1.000 0.179 Ed 0.286 0.179 1.000 Richard 0.393 0.143 -0.036 Richard John 0.107 Mike 0.321 Nick 0.036 Dick 0.393 Bob 0.143 Ed -0.036 Richard 1.000 Pairwise correlations in descending order 0.536 Dick and Bob Not significant 0.429 John and Mike Not significant 0.429 John and Dick Not significant 0.393 Dick and Richard Not significant 0.357 Nick and Ed Not significant 0.321 Mike and Richard Not significant 0.321 Mike and Nick Not significant 0.286 Dick and Ed Not significant 0.250 Mike and Dick Not significant 0.214 Nick and Dick Not significant 0.179 Bob and Ed Not significant 0.179 John and Bob Not significant 0.143 Bob and Richard Not significant 0.107 John and Richard Not significant 0.036 Nick and Richard Not significant -0.036 Ed and Richard Not significant -0.286 John and Nick Not significant -0.393 John and Ed Not significant -0.429 Mike and Bob Not significant -0.500 Mike and Ed Not significant -0.571 Nick and Bob Not significant
COMMENT: This tasting was comprised of wines from different regions of Italy as well as different vintages; furtermore these wines are made from diverse varietals. Perhaps we should not be surprised then that the stylistic preferences of our tasters resulted in a low correlation. All of us felt that with the exception of the Barbera which was 10 years old, from a varietal consumed young, all were of high quality. Surprisingly, the one Nebbiolo based wine, an Ilio Grasso Barolo, from the 2004 vintage, appeared mature and ready to drink. One taster remarked that nothing rises to the top of this class. One of the advantages of this type of tasting is that we get to compare different wineries with different vintages. Today, the 2003 vintage, which is a hot but not great vintage, produced two of the wines tied for the top. It may be worth to look out for bargains as retailers close out the 2003 vintage.
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