Labs for Data Analysis

Periodically we will devote a class session to applied data analysis. The purpose of the lab is two fold: (1) to assist with planning your analysis while pointing out some common problems that might occur in your own research, and (2) to provide some practical experience with using statistical software and interpreting thre results. You can prepare for the labs by considering how you would describe and analyze the following datasets, and then carrying out your analysis plan in whatever software program you would like. During the class, we will discuss your ideas for how to analyze the data, conduct the analysis using R, and interpret the results. Datasets are posted in excel format and text (comma separated value or csv).

In the future, let us know if you have a particular dataset that you would like to see analyzed from your own research. We will incorporate it into the course and/or a future lab as appropriate.

Lab 1

• Dataset 1: The investigators measured a pre (before intervention) value in 20 mice, assigned each mouse to treatment or placebo groups, and remeasured the same outcome after receiving the treatment/placebo. Is there a treatment effect?
  • prepost.xls
  • prepost.csv
• Dataset 2: The following contains the results from two studies in one file to simplify data importing into your software package. Both trials contain 40 subjects with the same values for age and gender. However, treatment/control status (trt1 or trt2) and the outcome (y1 or y2) differ for study 1 and study 2, so separate analyses should be performed. For both studies, the research question is the same: Is there an association between the treatment and the outcome?
  • trials.xls
  • trials.csv
• Note that there is something unusal occurring in each of these datasets so that just results from statisical tests may not appropriately answer the research questions.