The local Automobile Association conducted a study of the incidences over a ten-year period of children under the age of 5 years who were involved in motor vehicle accidents that resulted in road fatalities. The results for children who were not wearing set belts at the time of the accident are shown in the following table

 Age Male Female Total 0 265 227 492 1 204 191 395 2 367 207 574 3 316 190 506 4 477 194 671 Total 1629 1009 2638

Are these random variables discrete or continuous?  discrete

(b) What is the probability that a fatality involved a 3-year old? 506/2638 (253/1319=0.1918)

(c) What is the probability that the fatality involved a child who is 3-year old and is a male? 316/2638 (158/1319=0.1198)

(d) What is the probability that the fatality involved a child who is a 3-year old or is a male? 316+1629=1945/2638

(e) What is the probability that the fatality involved a child who is 3-year old given that the child is male? not sure

(f) Two fatalities are randomly selected, what is the probability that the first fatality involved a child who is less than 1 year old and the second fatality involved a child who is less than 1 year old?265+227=492/2638

I have placed my answers but just wanted to know if my answers are correct

Reduce the fractions to their lowest form.

(a), (b), (c) correct.

(d) p(male or 3-yr old)=p(male)+p(3-yr old)-p(male and 3-yr old)=(1629+506-316)/2638=1819/2638=0.6895. I understand “or” to mean one or the other but not both.

(e) 316/1629=0.1940.

(f) (492/2638)²=0.03478, if BOTH fatalities are for children under a year old. I think they’re right otherwise.

by Top Rated User (738k points)