A treatment group of 138 women received an enhanced leaflet about cervical cancer screening. A control group of 136 women received the standard leaflet. A week later, all women were asked if they were willing to be screened. In the treatment group, 109 women said yes; in the control group, 120 women said yes.

a) Construct a 95% confidence interval for the difference in proportions for the two populations represented by these samples.

b) Are the populations different?

c) Construct an 87% confidence interval for the difference in proportions for the two populations represented by these samples.