Question 7.115

7.115 Alcohol content of wine.

The alcohol content of wine depends on the grape variety, the way in which the wine is produced from the grapes, the weather, and other influences. Here are data on the percent of alcohol in wine produced from the same grape variety in the same year by 48 winemakers in the same region of Italy:39

wine

12.86 12.88 12.81 12.70 12.51
12.60 12.25 12.53 13.49 12.84
12.93 13.36 13.52 13.62 12.25
13.16 13.88 12.87 13.32 13.08
13.50 12.79 13.11 13.23 12.58
13.17 13.84 12.45 14.34 13.48
12.36 13.69 12.85 12.96 13.78
13.73 13.45 12.82 13.58 13.40
12.20 12.77 14.16 13.71 13.40
13.27 13.17 14.13
  1. Make a stemplot of the data. The distribution is a bit irregular, but there is no reason to avoid use of procedures for .
  2. Give a 95% confidence interval for the mean alcohol content of wine of this type.

7.115

(a) There are no outliers, so procedures can be used for . (b) (13.00, 13.31).