Statistics

Question

In a survey of adults 68% thought DNA tests for identifying an individual were very reliable. If you randomly select 44 adults and ask ear if he thinks the DNA tests for identifying an individual are very reliable. Decide whether you can use normal distribution to approximate binomial distribution. If so, find the probability that at most 15 people say DNA test for identifying an individual are try reliable?

Answer 1

mean = np = 44(0.68) = 29.92

standard deviation = npq = 44(0.68)(1-0.68)=9.5744

 

P(X≤15)= P (Z≤(15-29.92)/9.5744)=P(Z≤-1.56)

 

from Normal curve table  P(Z<-1.56)= 0.0594

 

The probability that at most 15 people say DNA test for identifying an individual are reliable is 5.94%