Question 637665
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Hi,
1) The probability that a person is immune to a certain disease is 0.40.
Note: The probability of x successes in n trials is: 
P = nCx* {{{p^x*q^(n-x)}}} where p and q are the probabilities of success and failure respectively.
 nCx = {{{n!/(x!(n-x)!)}}}
 a)what is the probability that 4 people will have the disease in a sample of 12 people? *[tex \large {{12}\choose{4}}] (.6)^4(.4)^8 
 b)find the mean number of people who have immunity in a sample size of 12. m = {{{12*.4}}}
 c) find the standard deviation for the sample size  SD = {{{sqrt(12*.4*.6)}}}