At a popular rock-climbing site in Yosemite National Park, a randomly selected sample of 200
climbers are asked whether they have ever had a climbing accident and whether they are
certified climbers. The results are shown below.
Suppose you are searching for a climbing partner at Yosemite and you meet Rob, Andrew, and
Sarah. Rob thinks of himself as a free spirit - he climbs without any certification. Andrew is
hoping to continue his life-long streak of never having a climbing accident. You don't know
anything about Sarah.
Use the frequency table below to calculate the following probabilities.
Round to the nearest hundredth of a percent.
Probability that Rob has had an accident =
Probability that Andrew is certified
Probability that Sarah is certified =
Certified
Has had an accident
2
Has never had an accident 138
%
%
Not certified
6
54
%
A
Row total
8
192