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Rotary oil rigs. An economist wants to compare the average
Chapter 9, Problem 58E(choose chapter or problem)
Rotary oil rigs. An economist wants to compare the average monthly number of rotary oil rigs running in three states—California, Utah, and Alaska. In order to account for month-to-month variation, 3 months were randomly selected over a 2-year period, and the number of oil rigs running in each state in each month was obtained from data provided from World Oil (Jan. 2002) magazine. The data, reproduced in the accompanying table, were analyzed using a randomized block design.
a. Why is a randomized block design preferred over a completely randomized design for comparing the mean number of oil rigs running monthly in California, Utah, and Alaska?
b. Identify the treatments for the experiment.
c. Identify the blocks for the experiment.
d. State the null hypothesis for the ANOVA F-test.
e. Locate the test statistic and p-value on the XLSTAT printout shown below. Interpret the results.
f. A Tukey multiple comparisons of means (at α = .05) is summarized in the XLSTAT printout below. Which state(s) have the significantly largest mean number of oil rigs running monthly?
Questions & Answers
QUESTION:
Rotary oil rigs. An economist wants to compare the average monthly number of rotary oil rigs running in three states—California, Utah, and Alaska. In order to account for month-to-month variation, 3 months were randomly selected over a 2-year period, and the number of oil rigs running in each state in each month was obtained from data provided from World Oil (Jan. 2002) magazine. The data, reproduced in the accompanying table, were analyzed using a randomized block design.
a. Why is a randomized block design preferred over a completely randomized design for comparing the mean number of oil rigs running monthly in California, Utah, and Alaska?
b. Identify the treatments for the experiment.
c. Identify the blocks for the experiment.
d. State the null hypothesis for the ANOVA F-test.
e. Locate the test statistic and p-value on the XLSTAT printout shown below. Interpret the results.
f. A Tukey multiple comparisons of means (at α = .05) is summarized in the XLSTAT printout below. Which state(s) have the significantly largest mean number of oil rigs running monthly?
ANSWER:
Step 1 of 8
a)
For comparing the mean number of oil rigs running monthly in California, Utah and Alaska, we use randomized complete block design. It will block out the variation of month, which could affect the number of rotary oil rigs running.