1 For each pair of twins, compute the following for the lumbar spine A BMD for the heavier smoking twin BMD for the lighter smoking twin x 1 x 2 B mean BMD for the twinship (x 1 x 2 ) 2 C 100 (A B) Derive appropriate descriptive statistics for C over the entire study population 2 Suppose we group t...

For lumbar spine bone mineral density we have the following Mean 49496682 Median 62893082 Sd 1248342 ...

1. For each pair of twins, compute the following for the lumbar spine: A = BMD for...

Question:

1. For each pair of twins, compute the following for the lumbar spine:

A = BMD for the heavier-smoking twin − BMD for the lighter-smoking twin = x₁ − x₂

B = mean BMD for the twinship = (x₁ + x₂)/2

C = 100% × (A/B)

Derive appropriate descriptive statistics for C over the entire study population.

2. Suppose we group the twin pairs according to the difference in tobacco use expressed in 10 pack-year groups (0–9.9 pack-years/10–19.9 pack-years/20–29.9 pack-years/30–39.9 pack-years/40+ pack-years). Compute appropriate descriptive statistics, and provide a scatter plot for C grouped by the difference in tobacco use in pack-years?

3. What impression do you have of the relationship between BMD and tobacco use based on Problem 2?