WEEK 7

· One way of seeing possible relationships between two variables is to look at the Conditional Distribution for each variable. A conditional distribution, looks at the distribution of one categorical variable within each of the categories of the other variable.

Example: Create a conditional distribution for the variable Had Depression.

Step 1: First, look at the column, Had Cancer? Yes. Calculate the proportion of those with cancer who also had depression. Then calculate the proportion of those with cancer who did not have depression. Notice that these proportions add up to 1 because they make up all of the people who had cancer.

· Conditional Distribution for “Had Depression”

· From this, we see that if a patient had cancer, he/she had a 77% probability of also having depression.

Step 2: Look at the column, Had Cancer?No. Calculate the proportion of those who did not have cancer, that had depression. Then, calculate the proportion of those who did not have cancer that did not have depression.

Conditional Distribution for “Had Depression”

From this, we see that if a patient did not have cancer, he/she had a 54% probability of having depression. Depression is more evenly distributed for patients without cancer than for patients with cancer.

· Exercise B1: Complete the Conditional Distribution Table for the variable Had Cancer. The first entry has been done for you.

· Exercise B2: Create the graph for the Conditional Distribution for Had Cancer?

Exercise B3: Interpret this conditional distributions for Had Depression? and Had Cancer?. Make at least two summary statements based on each distribution.