Assignment:
Q1 Calculate the test statistic and p-value for each sample.
a. H0: π ≤.60 versus H1: π > .60, α = .05, x = 56, n = 80
b. H0: π = .30 versus H1: π = .30, α = .05, x = 18, n = 40
c. H0: π ≥ .10 versus H1: π< .10, α = .01, x = 3, n = 100
Q2 The Tri-Cities Tobacco Coalition sent three underage teenagers into various stores in Detroit and Highland Park to see if they could purchase cigarettes. Of 320 stores checked, 82 sold cigarettes to teens between 15 and 17 years old.
(a) If the goal is to reduce the percent to 20 percent or less, does this sample show that the goal is not being achieved at α = .05 in a right-tailed test?
(b) Construct a 95 percent confidence interval for the true percent of sellers who allow teens to purchase tobacco.
Q3 What is the difference between an attribute control chart and a variable control chart?
Q4 Set up control limits for an ¯ x chart, given ¯¯ x = 400, ¯R = 5, and n = 4.
Q5 To print 8.5 × 5.5 note pads, a copy shop uses standard 8.5 × 11 paper, glues the long edge, then cuts the pads in half so that the pad width is 5.5 inches. However, there is variation in the cutting process. Set up a control chart for the mean width of a note pad, assuming that, in the future, pads will be sampled in random subgroups of 5 pads. Use this sample of 40 observations (widths in inches) to estimate μ and σ.
NotePads
5.52 5.57 5.44 5.47 5.52 5.46 5.43 5.45
5.49 5.47 5.48 5.51 5.53 5.53 5.48 5.47
5.59 5.51 5.43 5.48 5.53 5.50 5.49 5.52
5.46 5.46 5.56 5.54 5.47 5.44 5.53 5.58
5.55 5.56 5.47 5.44 5.55 5.42 5.45 5.54