Question

The table summarizes results from 984 pedestrian deaths that were caused by automobile accidents.

Driver Intoxicated?	Pedestrian Intoxicated?
	Yes	No
Yes	57	77
No	277	573

If two different pedestrian deaths are randomly selected, find the probability that they both involved pedestrians that were not intoxicated.

Report the answer as a percent rounded to one decimal place accuracy. You need not enter the "%" symbol. prob =

Answer 1

Solution:

Given:

	Pedestrian Intoxicated?
Driver Intoxicated?	Yes	No	Total
Yes	57	77	134
No	277	573	850
Total	334	650	N = 984

Two different pedestrian deaths are randomly selected.

Find:

P( both involved pedestrians that were not intoxicated ) =...........?

P( both involved pedestrians that were not intoxicated )

= P(first pedestrians that were not intoxicated) X P(second pedestrians that were not intoxicated)

= (650/984) X ( 649 / 983)

( note: for second , we reduce number by 1, since we counted it for first death)

= 0.6605691 X 0.6602238

=0.4361234

=0.436

=43.6%

thus

P( both involved pedestrians that were not intoxicated ) = 43.6%