number 16

According to the Rule ofThree, when we have a sample size n with x=0 successes, we have95% confidence that the true population proportion has an upper bound of 3n.

a. If n independent trials result in nosuccesses, whycan't we find confidence interval limits by using the methods described in thissection?

b. If 40 couples use a method of gender selection and each couple has a babygirl, what is the95% upper bound forp, the proportion of all babies who areboys?

a. Choose the correct answer below.

• The requirement of at least 5 successes and at least 5 failures is notsatisfied, so the normal distribution cannot be used.

• The requirement of at least 5 successes and at least 5 failures is notsatisfied, so the binomial distribution cannot be used.
• The requirement of dependent trials is notsatisfied, so the binomial distribution cannot be used.
• The requirement of dependent trials is notsatisfied, so the normal distribution cannot be used.

b. The95% upper bound forp, the proportion of all babies who areboys, is ----- (Round to three decimal places asneeded.)