COU 4: Computing Conditional Probabilities

In COU 3, we introduced a model in which the success of an attempted attack by a terrorist or guerilla group is conditional on the group’s competence. We imagined a citizen who is uncertain both about the group’s competence and about whether an attack staged by the group will be successful. Here is the diagram we built to depict the conditional probability distribution describing the citizen’s beliefs:

In each of the following prompts you are asked to compute a conditional probability using the diagram above. Importantly, you must include a marked-up version of the diagram showing how you did the calculation in response to each prompt. Giving the correct answer in response to a prompt without a marked-up diagram that shows how you used the diagram to do the calculation will get zero points.

Right-click or two-tap the diagram above above to save the image as a png file to your local machine. To show your work for each prompt, you can embed the png as an image in a note taking or word processing app and then mark it up and annotate it using the drawing tools in the app.

Prompt 1

What is the probability that the group’s competence is low conditional on the event that the attack is a “spectacular” success?

Prompt 2

What is the probability that the group’s competence is medium conditional on the event that the attack is a “spectacular” success?

Prompt 3

What is the probability that the group’s competence is high conditional on the event that the attack is a “moderate” success?

Prompt 4

What is the probability that the group’s competence is low conditional on the event that the attack is a “moderate” success?

Prompt 5

What is the probability that the group’s competence is medium conditional on the event that the attack is a “failure”?

Prompt 6

What is the probability that the group’s competence is high conditional on the event that the attack is a “failure”?

Rubric

For each prompt, you get two points if you provide a marked-up diagram and the marked-up diagram shows that you used the correct procedure to compute correct answer and you give the correct answer.

You get one point if you provide a marked up diagram that shows you used the correct procedure but you do not provide the right answer or you provide an incorrect answer.

You get zero points otherwise.