SOLUTION: A recent study of risk factors reported that 30% of adults met criteria for hypertension. If 15 adults are assessed, what is the probability that? A) Exactly 5 meet the criteria

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Question 1164567: A recent study of risk factors reported that 30% of adults met criteria for hypertension. If 15 adults are assessed, what is the probability that?
A) Exactly 5 meet the criteria for hypertension
B) None meet the criteria
C) Less than or equal to 7 meet the criteria

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
for 5
15C5(.3)^5*0.7^10=0.2061
For none it would be 0.7^15=0.0047
less than or equal to 7 would be 0.9500
can use crude normal approximation to check
np=4.5 mean
np(1-p)=3.15
sqrt(3.15) is sd=1.775
z<(7.5-4.5)/1.775
z<1.69
probability if 0.9545, which suggests answer is reasonable
Use 7.5 for the continuity correction factor
Calculator is 2VARS binomcdf (15,.3,7) ENTER