TABLE E2.18
LDL (mmol/L)
Subject Cornflakes Oat Bran
1 4.61 3.84
2 6.42 5.57
3 5.40 5.85
4 4.54 4.80
5 3.98 3.68
6 3.82 2.96
7 5.01 4.41
8 4.34 3.72
9 3.80 3.49
10 4.56 3.84
11 5.35 5.26
12 3.89 3.73
13 2.25 1.84
14 4.24 4.142.19 An experiment was conducted at the University of California–Berkeley
to study the e¤ect of psychological environment on the anatomy of the
brain. A group of 19 rats was randomly divided into two groups. Twelve
animals in the treatment group lived together in a large cage furnished
with playthings that were changed daily; animals in the control group
lived in isolation with no toys. After a month, the experimental animals
were killed and dissected. Table E2.19 gives the cortex weights (the
thinking part of the brain) in milligrams. Calculate separately for each
group the meanx, variances^2 , and standard deviationsof the cortex
weight.
TABLE E2.19
Treatment Control
707 696 669
740 712 650
745 708 651
652 749 627
649 690 656
676 642
699 6982.20 Ozone levels around Los Angeles have been measured as high as 220
parts per billion (ppb). Concentrations this high can cause the eyes to
burn and are a hazard to both plant and animal life. But what about
98 DESCRIPTIVE METHODS FOR CONTINUOUS DATA