probability question

Question

 

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

Answer 1

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.