Data used in the module Comparing Two Groups

The following data sets are used in this module. Select the links below to familiarize yourself with each of the datasets. Links are provided to download the data. Data sets are given in plain text format.

  1. Information about the Skeleton Data
    Download the Skeleton data file (plain text)
  2. Information about the HPV Vaccine Data
  3. Information about the Life Expectancy Data
    Download the Life Expectancy Data (plain text)
  4. The Schizophrenia Data
    In a 1990 study, researchers used MRI to measure the volumes of various regions of the brain. Measurements were taken on 15 monozygotic twins, where one twin was affected by schizophrenia (“affected”) and the other not (“unaffect”). The data we consider are the volumes of the left hippocampus region in cubic centimetres.

This example was taken from F. Ramsey and D. Schafer, The Statistical Sleuth: A Course in Methods of Data Analysis, 2nd edition, Duxbury, 2002, Case 2.1.2. The data are available in the R library Sleuth2 (external link, opens in new window) and the data values can be seen in the video The Sign Test and accompanying notes.

For the original study see:
R.L. Suddath, G.W. Christison, E.F. Torrey, M.F. Casanova, and D.R. Weinberger (1990). Anatomical Abnormalities in the Brains of Monozygotic Twins Discordant for Schizophrenia. The New England Journal of Medicine 322(12), 789-94.