Instructor's Resource Guide with Complete Solutions

Chapter 9 Quiz
For each of the following problems, please provide the requested information.
(a) State the null and alternate hypotheses and the level of significance. Is the test left-tailed, right-tailed,
or two-tailed?
(b) Identify the appropriate sampling distribution: the standard normal or the Student’s t. What is the
value of the sample test statistic?
(c) Sketch the critical region.
(d) Find the p-value or range containing the p-value.
(e) Based on your answers for parts (a) through (d), will you reject or fail to reject the null hypothesis?
Interpret your conclusion in the context of the application.
1. A large furniture store has begun a new ad campaign on local television. Before the campaign, the long
term mean daily sales were $24,819. A random sample of 40 days during the new ad campaign gave a
sample mean daily sale of x = $25,910. Does this indicate that the population mean daily sales is now
more than $24,819? Use a 1% level of significance. Assume  = $1917.
1. (a) __________________________
(b) __________________________
(d) __________________________
(e) __________________________
2. A new bus route has been established between downtown Denver and Englewood, a suburb of Denver.
Dan has taken the bus to work for many years. For the old bus route, he knows from long experience that
the mean waiting time between buses at his stop was  = 18.3 minutes. However, a random sample of 5
waiting times between buses using the new route had mean x = 15.1 minutes with sample standard
deviation s = 6.2 minutes. Does this indicate that the population mean waiting time for the new route is
less than what it used to be? Use  = 0.05.
2. (a) __________________________
(b) __________________________
(d) __________________________
(e) __________________________
3. The State Fish and Game Division claims that 75% of the fish in Homestead Creek are rainbow trout.
However, the local fishing club caught and released 189 fish one weekend. They found that 125 were
rainbow trout. Does this indicate that the percentage of rainbow trout in Homestead Creek is less than
75%? Use  = 0.01.
3. (a) __________________________
(b) __________________________
(d) __________________________
(e) __________________________