It can be dangerous for a left-hander to live in a right-handed world. Everything from can-openers to power tools are designed for right-handed people. Does this make left-handers more accident-prone than right-handers? A study looked at the rate of accidental death among left-handers and right-handers.

They found the probability that a left-hander suffered accidental death was 5.7 times the probability that a right-hander suffered accidental death.

This sort of statement is described as a relative risk, because one conditional probability is expressed as a multiple of another. The sample space is

Ω = {people in the population under study}.The proportion of left-handers in the population is 10%. Define events L, R, and A for the events that a person in the population is respectively left-handed, right-handed, and suffers accidental death.

It’s not just humans, either. A study in the Journal of Zoology (Seligmann et al, 2003) reported extensively on the disadvantages of being left-footed in 193 species of lizards.

No kidding, left-footed lizards are way more accident-prone than rightfooted lizards.

a. Write down all the information given in the question, in the form of probability statements.

b. Find the probability that a person who suffers accidental death is left-handed. (Hint: look for quantities that cancel out of fractions.)

c. In part (b), left-handers constitute 10% of the overall population. What percentage do they constitute of people who have accidental deaths?