Pairwise comparisons of population means
There are four major blood types in humans: O, A, B and AB. In a
study conducted using blood specimens from the Blood Bank of Hawaii,
individuals were classified according to blood type and ethnic
group. The ethnic groups considered were Hawaiian, Hawaiian-white,
Hawaiian-Chinese, and white. Assume that the blood bank specimens
are random samples from the Hawaiian populations of these ethnic
groups.
Blood
Type
===== |
Hawaiians
======== |
Hawaiian-
White
======== |
Hawaiian-
Chinese
======== |
White
======= |
Total
======= |
| O |
1,903 |
4,469 |
2,206 |
53,759 |
62,337 |
| A |
2,490 |
4,671 |
2,368 |
50,008 |
59,537 |
| B |
178 |
606 |
568 |
16,252 |
17,604 |
| AB |
99 |
236 |
243 |
5,001 |
5,579 |
| Total |
4,670 |
9,982 |
5,385 |
125,020 |
145,057 |
- What kinds of inference procedures/tests might you perform
on this data, and what kinds of questions would these
attempt to answer?
- Suppose you were curious about whether the proportion
of people from the various ethnic groups who had
blood type O were different. Perform pairwise
comparisons of the difference of 2 proportions
to see if this data supports that there is a
difference between at least one pair at the
5% level.
[Data Source: A. E. Mourant et al., “The Distribution of
Human Blood Groups and Other Polymorphisms”.
See also Exercise 9.24, Moore/McCabe “Introduction to the
Practice of Statistics”.]
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