Concerned about graffiti, mayors of nine suburban communities instituted a citizen Community Watch program.
(a) Choose the appropriate hypotheses to see whether the number of graffiti incidents declined. Assume μd is the mean difference in graffiti incidents before and after.
a. H1: μd ≤ 0 versus H0: μd > 0.
b. H0: μd ≥ 0 versus H1: μd < 0.
(b) Find the test statistic tcalc. (A negative amount should be indicated by a minus sign. Round your answer to 2 decimal place.)
(c) State the critical value tcrit for α = .05. (A negative amount should be indicated by a minus sign. Round your answer to 3 decimal place.)
(d) Find the p-value.