Question 1.1. Brian Vanecek, VP of Operations at Portland Trust Bank, is evaluating the service level provided to walk-in customers. Accordingly, his staff recorded the waiting times for 45 randomly selected walk-in customers, and calculated that their mean waiting time was 15 minutes. If Brian concludes that the average waiting time for all walk-in customers is 15 minutes, he is using a/an ________. (Points : 3)
range estimate
statistical parameter
interval estimate
point estimate
exact estimate
statistical parameter
interval estimate
point estimate
exact estimate
Question 2.2. Brian Vanecek, VP of Operations at Portland Trust Bank, is evaluating the service level provided to walk-in customers. Accordingly, his staff recorded the waiting times for 64 randomly selected walk-in customers and determined that their mean waiting time was 14 minutes. Assume that the population standard deviation is 4 minutes. The 90% confidence interval for the population mean of waiting times is ________. (Points : 3)
14.27 to 15.73
14.18 to 15.82
9.88 to 20.12
13.18 to 14.82
18.12 to 19.87
14.18 to 15.82
9.88 to 20.12
13.18 to 14.82
18.12 to 19.87
Question 3.3. The normal distribution is used to test about a population mean for large samples if the population standard deviation is known. "Large" is usually defined as _______. (Points : 3)
at least 10
at least 5% of the population size
at least 30
at least 12
at least 100
at least 5% of the population size
at least 30
at least 12
at least 100
Question 4.4. Consider the following null and alternative hypotheses.
Ho: p < 0.16
Ha: p > 0.16
These hypotheses _______________. (Points : 3)
Ho: p < 0.16
Ha: p > 0.16
These hypotheses _______________. (Points : 3)
indicate a one-tailed test with a rejection area in the right tail
indicate a one-tailed test with a rejection area in the left tail
indicate a two-tailed test
are established incorrectly
are not mutually exclusive
indicate a one-tailed test with a rejection area in the left tail
indicate a two-tailed test
are established incorrectly
are not mutually exclusive
Question 5.5. A company produces an item that is supposed to have a 6-inch hole punched in the center. A quality control inspector is concerned that the machine that punches the hole is "out of control" (hole is too large or too small). In an effort to test this, the inspector is going to gather a sample punched by the machine and measure the diameter of the hole. The alternative hypothesis used to statistically test to determine if the machine is out of control is (Points : 3)
the mean diameter is > 6 inches
the mean diameter is < 6 inches
the mean diameter is = 6 inches
the mean diameter is ≠ 6 inches
the mean diameter is ≥ 6 inches
the mean diameter is < 6 inches
the mean diameter is = 6 inches
the mean diameter is ≠ 6 inches
the mean diameter is ≥ 6 inches
Question 6.6. A researcher is testing a hypothesis of a single mean. The critical z value for a = .05 and a two‑tailed test is +1.96. The observed z value from sample data is ‑2.05. The decision made by the researcher based on this information is to _____ the null hypothesis. (Points : 3)
reject
not reject
redefine
change the alternate hypothesis into
restate the null hypothesis
not reject
redefine
change the alternate hypothesis into
restate the null hypothesis
Question 7.7. Jennifer Cantu, VP of Customer Services at Tri-State Auto Insurance, Inc., monitors the claims processing time of the claims division. Her standard includes "a mean processing time of 5 days or less." Each week, her staff checks for compliance by analyzing a random sample of 60 claims. Jennifer's null hypothesis is ________. (Points : 3)
m > 5
s > 5
n = 60
m < 5
m = 5
s > 5
n = 60
m < 5
m = 5
Question 8.8. Restaurateur Denny Valentine is evaluating two sites, Raymondville and Rosenberg, for his next restaurant. He wants to prove that Raymondville residents (population 1) dine out more often than Rosenberg residents (population 2). Denny plans to test this hypothesis using a random sample of 81 families from each suburb. His null hypothesis is __________. (Points : 3)
s12 < s22
mm1 - mm2 ³ 0
p1 – p2 = 0
m1 - m2 = 0
s1 – s2 = 0
mm1 - mm2 ³ 0
p1 – p2 = 0
m1 - m2 = 0
s1 – s2 = 0
Question 9.9. Lucy Baker is analyzing demographic characteristics of two television programs, COPS (population 1) and 60 Minutes (population 2). Previous studies indicate no difference in the ages of the two audiences. (The mean age of each audience is the same.) Lucy plans to test this hypothesis using a random sample of 100 from each audience. Her alternate hypothesis is ____________. (Points : 3)
m1 - m2 < 0
m1 - m2 ³ 0
m1 - m2 = 0
m1 - m2 ¹ 0
m1 - m2 = 1
m1 - m2 ³ 0
m1 - m2 = 0
m1 - m2 ¹ 0
m1 - m2 = 1
Question 10.10. Maureen McIlvoy, owner and CEO of a mail order business for wind surfing equipment and supplies, is reviewing the order filling operations at her warehouses. Her goal is 100% of orders shipped within 24 hours. In previous years, neither warehouse has achieved the goal, but the East Coast Warehouse has consistently out-performed the West Coast Warehouse. Her staff randomly selected 200 orders from the West Coast Warehouse (population 1) and 400 orders from the East Coast Warehouse (population 2), and reports that 190 of the West Coast Orders were shipped within 24 hours, and the East Coast Warehouse shipped 372 orders within 24 hours. Maureen's null hypothesis is ____. (Points : 3)
p1 – p2 = 0
m1 - m2 = 0
p1 – p2 > 0
m1 - m2 < 0
m1 - m2 ≥ 0
m1 - m2 = 0
p1 – p2 > 0
m1 - m2 < 0
m1 - m2 ≥ 0
