Learn By Doing

Background to Dataset

Clinical depression is the most common mental illness in the United States, affecting 19 million adults each year (Source: NIMH, 1999). Nearly 50% of individuals who experience a major episode will have a recurrence within 2 to 3 years. Researchers are interested in comparing therapeutic solutions that could delay or reduce the incidence of recurrence.

In a study conducted by the National Institutes of Health, 109 clinically depressed patients were separated into three groups, and each group was given one of two active drugs (imipramine or lithium) or no drug at all. For each patient, the dataset contains the treatment used, the outcome of the treatment, and several other interesting characteristics.

Here is a summary of the variables in our dataset:

Hospt: The patient's hospital, represented by a code for each of the 5 hospitals (1, 2, 3, 5, or 6)
Treat: The treatment received by the patient (Lithium, Imipramine, or Placebo)
Outcome: Whether or not a recurrence occurred during the patient's treatment (Recurrence or No Recurrence)
Time: Either the time in days till the first recurrence, or if a recurrence did not occur, the length in days of the patient's participation in the study
AcuteT: The time in days that the patient was depressed prior to the study
Age: The age of the patient in years, when the patient entered the study
Gender: The patient's gender (1 = Female, 2 = Male)

Learn By Doing

Question prompt

Question:

Question

A Choice 1

B Choice 2

Correct? Comments.

Hint Comments.

Opening the Dataset - Looking Forward

To open the data, right-click on the file name, depression.xls, and choose “Save Link As” (or “Save Target As”) to download the file to your computer. Then find the downloaded file and double-click it to open it in Excel (or Open Office, etc.).

This dataset is also available as a comma separated file (CSV), depression.csv which can be opened in any text editor, although the data are not as visually organized in this type of file.

In future assignments you will need to download datasets in this manner in order to import them, i.e. you will need to have the file saved to your computer.

In Excel, the dataset is in tabular form. Each row contains the values of the variables associated with a single individual, and the different variables are separated into columns. It is helpful if the columns are labeled with the variable names, as we have in this case.