statistics
posted by max .
72% working women use computers choose 5 at random
whats the probility at least 1 does not use a computer
whats the probility that all 5 use a computer

a) the probability that at least 1 doesnt use a computer at work
Because the question asks for at least 1 that doesn't we have to do the opposite complement.
P(E)=1P(complement)
Probablity of not using computer(NUC)=1  Probability of using computer P(NUC)= 1P(UC)
P(UC)= 0.72
P(using computer 5 times)=(0.72)(0.72)(0.72)(0.72)(0.72) or (0.72)^5=0.19349
P(NUC)= 1(0.72)^5= 0.807
b) The probability that all 5 use a computer in their jobs
P(C)=P(C*C*C*C*C)=(0.75)(0.75)(0.75)(0.75)(0.75)=(0.75)^5=.194