Question

A survey about same-sex marriage used a random sample with 1000 adults. The results showed that 40% favored legal marriage, 35% favored civil unions, and 25% favored no legal recognition.

a. Find the right boundary of the 92% C.I. for the proportion of adults who favor the “legal marriage” position.

b. Find the right boundary of the 94% C.I. for the proportion of adults who favor the “civil union” position.

c. Find the right boundary of the 96% C.I. for the proportion of adults who favor the “no legal recognition” position.

Answer 1

We know that % confidence interval for true proportion is given by:

So, the right boundary is given by:

a)

Right boundary for 92% CI is given by:

b)

Right boundary for 94% CI is given by:

c)

Right boundary for 96% CI is given by: