Statistics Course - January 2008

Nemours Biomedical Research Statistics Course

Dataset 1

    The first sixty children between 4 and 12 years of age who agreed to participate in a study on the benefits of two new dietary supplements were recruited during well-visits to two local pediatricians. The supplements purported to increase Pediatric Longterm Undeniable Coolness (PLUC) when taken consistently. Children were randomly assigned to one of three groups: a control group, whose dietary supplement was a placebo; and two treatment groups, one receiving Supplement A, and the other receiving Supplement B. At the beginning of the study, investiators recorded the age, height, gender and baseline PLUC for each participant. After six weeks of dietary supplementation (monitored at home by parents), all children returned to their pediatrician for a second PLUC measurement. At the time of the return visit, children were also administered a written test (the Lake Woebegone Averageness Scale or LWAS). The LWAS scores can range from 0 to 100, with 50 being 'Average'. Children from Lake Woebegone--and many other places--typically score about 75 on this test. As an additional factor, each of the two pediatricians participating in the study provided sunglasses for the children to wear during the study. The sunglasses either had rose-colored lenses, or the kind of lenses that look like mirrors from the outside. The investigators were careful to ensure that an equal number of children were fitted with each type of sunglasses. It was hypothesized that some sunglasses impart greater PLUC than others independent of dietary suplementation.

Variable names

  • sid - The subject ID
  • age - The subject's age in months
  • sex - The subject's gender (either 'm' or 'f')
  • hgt - The subject's height in inches.
  • grp - A single digit indicating the treatment group the subject was assigned to. 1 = Control, 2 = Supplement A, 3 = Supplement B.
  • PLUC.pre - The measure of PLUC at the start of the study.
  • PLUC.post - The measure of PLUC at the end of the study.
  • LWAS - The measure of LWAS obtained at the end of the study.
  • Shades - The type of sunglasses given the child (coded as 1 or 2 -- we are blinded as to the type assigned to each code).
  • Ped - a code (either 1 or 2) to identify which pediatrician recruited the subject.

Data file

    default.csv (you might need to right-click on this and select "Save as" in some browsers)
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