Question

The Ankle-Brachial Index (ABI) compares the blood pressure of a patient's arm to the blood pressure of a patient's leg. The ABI can be an indicator of different diseases (especially arterial disease). A healthy ABI is 0.90 or higher. In a study of 187 women who had peripheral arterial disease, researchers found that the sample had an average ABI of 0.64 with a standard deviation of 0.15; at the conventional level, do the data provide evidence to conclude that, on average, women with peripheral arterial disease have an unhealthy ABI?

Answer 1

H0: >= 0.90

Ha: < 0.90

Test statistics

t = ( - ) / ( S / sqrt(n) )

= (0.64 - 0.90 ) / (0.15 / sqrt(187) )

= -23.70

Critical value at 0.05 level with 186 df = -1.653

Since test statistics falls in rejection region, Reject H0.

We conclude at 0.05 level that we have sufficient evidence to support the claim.