Computing for research 1

SAS Graph / Proc Gplot

Homework Assignment

Lecture Date 1/29/2014

Due Date 2/05/2014

Data File HW_gplot_1_29_2014.sas7bdat

Description:

You have been given data that describes the longitudinal HDL cholesterol profile of a group of Type 1 diabetic subjects. One group has been prescribed a diet designed to specifically increase HDL cholesterol while the other is continued with treatment as usual. HDL-C was measured at study baseline/randomization and every 3 months for the next 2 years. At the end of the study, the groups were told to go back to usual dietary habits and followed for another 1 year. HDL-C levels were measured every 3 months during the entire study time course on all participants.

At baseline all of the subjects are removed from any lipid altering agents that they are currently taking. The investigator is preparing a presentation to discuss her findings at a conference and would like for you to prepare a figure that describes the longitudinal aspects of the HDL data in such a way that her clinical colleges may understand.

The data file contains information of 190 participants with 13 total measurements (1 baseline, 8 while under treatment and 4 during follow-up). There are 97 subjects in group 1 and 93 subjects in group 2; matched on age, race, gender, and smoking status.

Create a plot(s) that has correct axis labels with the necessary units, a well defined legend, means and standard errors over time, and is appropriate for a professional presentation. Create a figure that will stand alone and one where no other information is needed to interpret the data.

Submit a separate file for the plot and a file of well commented SAS code.

Data File Variables

ID: Subject ID

Time: Time (in quarters ) from study entry (0=baseline, 1=3months, 2=6 months…);

Grp: Diet Treatment group.

Group 1=Dietary Change Group

Group 2=Control Group

Y: HDL cholesterol reading in mg/dl