data fw13p09; title 'Chapter 13, Exercise 9, Sweet Potatoes';
input   VARIETY $  YIELD;
cards;
a         8.3
a         9.4
a         9.1
a         9.1
a         9.0
a         8.9
a         8.9
b         9.1
b         9.0
b         8.1
b         8.2
b         8.8
b         8.4
b         8.3
c        10.1
c        10.0
c         9.6
c         9.3
c         9.8
c         9.5
c         9.4
d         7.8
d         8.2
d         8.1
d         7.9
d         7.7
d         8.0
d         8.1