Reference no: EM137729

1. A radio station wants to know if residents in their area are in favor of a proposed tax increase. They invite listeners to call in to respond to the poll. 645 of the 800 who responded were against the tax. The station calculated a 95% confidence interval and declared "Between 77.9% and 83.4% of residents oppose the new tax."

A. This is a valid interval, so the station must be right.
B. We can't say for certain that between 77.9% and 83.4% of residents oppose the new tax because it is a 95% confidence interval.
C. Because of the way the poll was conducted, the results are invalid.

2. I want to construct a 92% confidence interval. The correct z* to use is

A. 1.75.
B. 1.41.
C. 1.645.

3. Several years ago, some researchers at my university asked me to recheck the statistics on a paper they were writing about the impacts of a group of new science courses. They had performed 63 statistical tests on their data at = 5%, and had found 4 "significant" results. They were excited. Should they have been?

A. Yes - this could be important.
B. Maybe - depends on the actual results.
C. No - too many tests were done.