# Response/opinion to probability post | MATH 311 – Probability and Statistics I | Liberty University

“A contingency table provides a way of portraying data that can facilitate calculating probabilities (Holmes, A., Illowsky, B., & Dean, S. 2017)”. I was unable to survey half and half, however, I was pretty close. I learned that right handed people far outweighed left handed people.

Part 1: A survey of 30 people to find out if they are left-handed or right-handed

Table 1: Contingency table

Left-handed Right-handed Total

Female 5 (A) 11 (B) 16(A+B)

Male 3 (C) 11(D) 14 (C+D)

Total 8(A+C) 22(B+D) 30(A+B+D)

Part 2

A. If a person is randomly selected from the survey participants, what is the probability that the person will be left-handed?

Solution:

(A+C)/(A+B+C+D): 5/30 = 0.167

B. If you randomly choose a female from the people you surveyed, what is the probability that she is left-handed?

Solution:

A/(A+B): 5/16 = 0.313

C. What is the odds ratio of choosing a left-handed female?

Solution

PROBABILITY 3 AD/BC: (5*11)/(11*3) = 55/33 = 1.667

D. What is the relative risk of choosing a left-handed female?

Solution

[A/(A+C)]/[B/(B+D)]: (5/8)/(11/22) = 0.625

Part 3:

According to Orr (2001), the percentage of left-handed people ranges between 10% and 13% of the world population. At one time, being left handed was often treated as a disorder. Teachers and parents would force children to transition into using their right hands.

References

Orr, T. (2017). Being a lefty is all right. Current Health, 28(2), 12-13

Holmes, A., Illowsky, B., & Dean, S. (2017). *Introductory business statistics*. OpenStax. https://openstax.org/details/books/introductory-business-statistics