## Class 31: Income and Mortality

On Friday we will meet in McCosh 66 to use the computer display equipment. On Monday
we will have a guest speaker.

### Discussion

Read the article "Income Inequality, mortality linked" from the Boston Globe on April
19.

What are some ways you could measure income disparity in a state? Do you have any
ideas why Kennedy's group and Kaplan's group chose the measures that they did?

How do you calculate the mortality rate of a state? What do you think an age-adjusted
mortality rate is? Why would you want to adjust for age?

In the article by Kennedy et. al. in the British Medical journal, the authors remark
that

"Another linitation of the present ecological study is its potential suseptability
to aggregation bias and unknown sources of confounding." What do you think they
mean?

How would you explain the correlation between age-adjusted mortality rates and income
disparity?

Here is a table that summarizes income information from Massachussetts in 1990. The
set of households of Massachussetts is divided into tenths, where the first tenth
is the households who earn the least and the last tenth is the households who earn
the most. The percentage of the total income of Massachussetts earned by each tenth is
given at right.

tenth percentage of total income

1 1.08

2 2.48

3 4.13

4 5.74

5 7.33

6 8.97

7 10.83

8 13.08

9 16.41

10 29.93

See if you can figure out how to use this table to calculate Kaplan's group's measure
of income distribution and to estimate the Robin Hood index for Massachussetts.