In: Math
Changes in demographic outcomes can occur because of changes in within-group rates and/or changes in composition. First, explain what that sentence means. Then take the example of falling rates of death due to heart disease. How might changes in within-group rates account for that outcome? What about changes in composition? Can you think of any way to sort out the effects of changes in within-group rates vs. changes in composition?
Changes in a demographic outcomes could occur in 2 ways
1. Change can occur in the the values of exsisting data
2. Change can occur if the data points change ie if some values are dropped and some new values get added to the data
Falling heart rates of death due to heart diesease
Within group
Within group means that people in the group remain the same but the values of the heart rates change for some people
This change of values for some people will be the within group changes
Changes in Composition
Here lets say there are 50 people in a group
Out of the 50 people 10 people leave to another city
So we have only 40 people remaining and it can happen that the heart rate of 50 people was different from the heart rate of the remaning 40 people
To sort out the effects of change in within group rate compared to changes n composition we need to apply ANOVA or the amalysis of variance in the data to find what percent of the change is contributed to within group and between group and a change in compostion