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Statistics LibreTexts

6.7: Statistical Literacy

Skills to Develop

  • Design a statistical study involving niacin, HDL and heart disease

Low HDL and Niacin

A low level of High-density lipoproteins (HDL) have long been known to be a risk factor for heart disease. Taking niacin has been shown to increase HDL levels and has been recommended for patients with low levels of HDL. The assumption of this recommendation is that niacin causes HDL to increase thus causing a lower risk for heart disease.

Example  \(\PageIndex{1}\): What do you think?

What experimental design involving niacin would test whether the relationship between HDL and heart disease is causal?


You could randomly assign patients with low levels of HDL to a condition in which they received niacin or to one in which they did not. A finding that niacin increased HDL without decreasing heart disease would cast doubt on the causal relationship. This is exactly what was found in a study conducted by the NIH. See the description of the results here.


  • Online Statistics Education: A Multimedia Course of Study ( Project Leader: David M. Lane, Rice University.