A rapid test for the presence in the blood of antibodies to HIV, the virus that causes AIDS, gives a positive result with probability about 0.004 when a person who is free of HIV antibodies is tested. A clinic tests 740 people who are all free of HIV antibodies.
(a) What is the distribution of the number of positive tests? normal or binomial? with n = and p = (Use 3 decimal places.)
(b) What is the mean number of positive tests? (Use 2 decimal places.)
(c) Is it possible to safely use the Normal approximation for this distribution?
No, the distribution is not binomial.
Yes, both np and n(1-p) are large.
No, np is too small.
Yes, both np and n(1-p) are small.
No, n(1-p) is too small.