MATH 225N Week 4 Discussion; Probability

Week 4 Discussion: Probability
Required Resources
Read/review the following resources for this activity:
 OpenStax Textbook: Chapter 2, 3
 Lesson
 Minimum of 1 scholarly source
In your reference for this assignment, be sure to include both your text/class materials AND your
outside reading(s).

Initial Post Instructions

Probability plays a major role in the medical community. Diagnoses are based on probabilities.
They are really questions or "what if's", and are answered by the probability that the treatment
will be the best for the ailment.

Let's look at probability in terms of both the real world and the medical community.

1. Survey 30 people to find out if they are left-handed or right-handed, and use the
following chart to create a contingency table with the information.

Left handed Right handed Total Female Male Total

2. Answer the following questions about the information in your contingency table:
a. If a person is randomly selected from the survey participants, what is the
probability that the person will be left-handed?
b. If you randomly choose a female from the people you surveyed, what is the
probability that she is left-handed?
c. What is the odds ratio of choosing a left-handed female?
d. What is the relative risk of choosing a left-handed female?

Example

Green Blue Total
Cats 40 (A) 20 (B) 60 (A+B)
Dogs 30 (C) 40 (D) 70 (C+D)
70
Total 60 (B+D) 130 (A+B+C+D)
(A+C)

a. Probability of Green - (A+C)/(A+B+C+D): 70/130 = 54%
b. Probability of Green Cat - A/(A+B): 40/60 = 67%