Go Green
A survey report shows that in an office 47% of the senior management and 34% of executives implemented the motto "Save Water, Save Trees, Go Green" in routine office activities.
A 95% confidence interval for the difference in these proportions is (-0.15 to -0.09), or, in other terms of percentage points, (-15% to -9%).
(Use the executives as population 1.) Interpret this confidence interval. If the interval contains 0, indicate what this means.
Explain the meaning of positive and/or negative values.