Question

a 2016 national public radio report described a study comparing patients who had their first ever traumatic brain injury 18 months earlier with similar healthy individuals with no prior brain trauma. The news report states that, 18 months after their traumatic brain injury, the patients "were still getting, on average, an hour more sleep each night than similar healthy people were getting. And despite the extra sleep, 67 percent showed signs of excessive daytime sleepiness. Only 19% of healthy people had that problem.

a) Identify the individuals in the study.

b) identify the variables recorded and whether they are categorical or quantitative.

Answer 1

a) The individuals comprising the sample space for this study were a mix of patients of brain trauma and other healthy individuals. The size of the sample is surely large enough for the mentioned proportions (percentages) for sleep-related behaviors to make sense. For making such observations, the subjects can be picked up from some brain trauma or rehab center, and compare with those who never enrolled or got involved in any such events in the past.

b) Variables recorded in the study are:

1. Had Brain Injury: Categorical (Yes/No)

2. Night Sleep Hours: Quantitative (can be any number of hours between 0 and 24)

3. Day Sleep Hours: Quantitative  (can be any number of hours between 0 and 24)