A survey was done among people aged 65 years or older.It was
found that they had a 30% of suffering from stroke.If they suffered
from stroke,then their chances of developing cardiovascular
complications were 70%.However,if they did not suffer fromj stroke
then they had a 25% chance of developing cardiovascular complications.
Find the probability of:
I)Experiencing one of the stated health problems.
ii)Experiencing at least one of the stated health problems.
b)A tire manufacturer designed a new ambulance tread pattern for its
all-weather tires.Repeated tests were conducted on ambulances of
approximately the same weight travelling at 60 kilometres per hour.The
tests showed that the new tread pattern enables the ambulances to stop
completely in an average distance of 125 metres with a standard
deviation of 6.5 meters and that the stopping distances are
approximately normally distributed.
I)What is the 70th percentile of the distribution of stopping distances?
ii)What is the probability that at least 2 ambulances out of 5
randomly selected cars in the study will stop in a distance that is
greater than the distance calculated in part(I) above?
iii)What is the probability that a randomly selected sample of 5
ambulances in the study will have a mean stopping distance of at least
130 feet?