An Internet report from January 2005 is titled, "Study: Anti-Seizure Drug Reduces Drinking in Bipolar Alcoholics." A chisquare test was carried out based on results mentioned in the report, which explains that takers of the drug (Valproate) and placebo were questioned after 6 months to see if they had engaged in heavy drinking (five or more drinks daily for men, four or more daily for women).
a. Did the sample of Valproate-takers have a lower percentage engaging in heavy drinking?
b. The P-value was found to be 0.077. Was the chi-square statistic much less than 3.84, somewhat less than 3.84, somewhat greater than 3.84, or much greater than 3.84?
c. In order to produce more convincing evidence of the drug's benefits, what would be the most obvious change to make if a second study could be carried out?
d. What would the P-value have been if a one-sided z test had been carried out to see if population proportion engaging in heavy drinking is less for Valproatetakers than for placebo-takers?
e. The chi-square statistic was 3.13. What would the z statistic have been if a z test had been carried out instead of a chisquare test?