Question

4. In an issue of Parade Magazine, the editors reported on a national survey on law and order. One question asked of the 2512 U.S. adults who took part was whether they believed that juries "almost always" convict the guilty and free the innocent. Only 578 said that they did. Do the data provide sufficient evidence to conclude that less than one in four Americans believe that juries "almost always" convict the guilty and free the innocent?

a. Use either the critical-value approach or the P-value approach to perform the appropriate hypothesis test at the 5% significance level.

b. Assess the strength of the evidence against the null hypothesis by referring to Table of “Using the P-value to assess the evidence against the null hypothesis” in Chapter 9.

5. In a January, 2006 Harris Poll of 1961 randomly selected U.S. adults, 1137 said that they do not believe that abstinence programs are effective in reducing or preventing AIDS. At the 5% significance level, do the data provide sufficient evidence to conclude that a majority of all U.S. adults feel that way?

Answer 1