One of the goals of the Edinburgh Artery Study was to invest

One of the goals of the Edinburgh Artery Study was to investigate the risk factors for peripheral arterial disease among persons 55 to 74 years of age. YOu wish to compare mean LDL cholesterol levels, measured in mmol/liter, among four different populations of subjects: patients with intermittent claudication or interrupotions in movement, those with major asymptomatic disease, those with minor asymptomatic disease, and those with no evidence of diesase at all.

Groups:

Intermittent Claudication: n = 73, = 6.22, s = 1.62

Major Asymptomatic Disease: n = 105, = 5.81, s = 1.43

Minor Asymptomatic Disease: n = 230, = 5.77, s = 1.24

No Disease: n = 1080, = 5.47, s = 1.31



A) Test the null hypothesis that the mean LDL cholesterol levels are the same for each of the four populations. What are the degrees of freedom associated with this test?

B) What do you conclude?

C) What assumptions about the data must be true for you to use the one-way analysis of variance technique?

D) Is it necessary to take an additional step in this analysis? If so, what is it? Explain.

Solution