Question

In March 2015, the Public Policy Institute of California (PPIC) surveyed 7525 likely voters living in California. PPIC researchers find that 68 out of 200 Central Valley residents approve of the California Legislature and that 156 out of 300 Bay Area residents approve of the California Legislature. PPIC is interested in the difference between the proportion of Central Valley and Bay Area residents who approve of the California Legislature. PPIC researchers calculate that the standard error for the proportion of Central Valley residents who approve of the California Legislature minus Bay Area residents who approve of the California Legislature is about 0.044.

Find the 95% confidence interval to estimate the difference between the proportion of Central Valley and Bay Area residents who approve of the California Legislature.

1. (-0.224, -0.136)
2. (0.094, 0.266)
3. (-0.266, -0.094)
4. (0.136, 0.224)

Answer 1