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free/or 0.5$ |
| m103 | A regional commuter airline selected a random sample of 25 flights and found that the correlation between the number of passengers and the total weight, in pounds, of luggage stored in the luggage compartment is 0.94. Using the .05 significance level, can we conclude that there is a positive association between the two variables? |
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| m104 | A regional planner is studying the demographics in a region of a particular state. She has gathered the following data on nine counties.
a. Is there a linear relationship between the median income and median age?
b. Which variable is the “dependent” variable?
c. Use statistical software to determine the regression equation. Interpret the value of the slope in a simple regression equation.
d. Include the aspect that the county is “coastal” or not in a multiple linear regression analysis using a “dummy” variable. Does it appear to be a significant influence on incomes?
e. Test each of the individual coefficients to see if they are significant.
f. Make a plot of the residuals and comment on whether they appear to follow a normal distribution.
g. Plot the residuals versus the fitted values. Do they seem to have the same amount ofvariation? |
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| m105 | A regression analysis relating the current market value in dollars to the size in square feet of homes in Greene County, Tennessee, follows. The regression equation is: Value 5 237,186 1 65.0 Size.
a. How many homes were in the sample?
b. Compute the standard error of estimate.
c. Compute the coefficient of determination.
d. Compute the correlation coefficient.
e. At the .05 significance level, does the evidence suggest a positive association between the market value of homes and the size of the home in squarefeet? |
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| m106 | A research firm wants to compare the miles per gallon of unleaded regular, mid-grade, and super premium gasolines. Because of differences in the performance of different automobiles, seven different automobiles were selected and treated as blocks. Therefore, each brand of gasoline was tested with each type of automobile. The results of the trials, in miles per gallon, are shown in the following table. At the .05 significance level, is there a difference in the gasolines orautomobiles? |
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| m107 | A sample of 12 homes sold last week in St. Paul, Minnesota, revealed the following information. Draw a scatter diagram. Can we conclude that, as the size of the home (reported below in thousands of square feet) increases, the selling price (reported in $ thousands) alsoincreases? |
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| m108 | A sample of 2,000 licensed drivers revealed the following number of speeding violations.
Number of Violations Number of Drivers
0 ............ 1,910
1 ............ 46
2 ............ 18
3............ 12
4 ............ 9
5 or more .......... 5
Total ............ 2,000
a. What is the experiment?
b. List one possible event.
c. What is the probability that a particular driver had exactly two speeding violations?
d. What concept of probability does this illustrate? |
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| m109 | A sample of 25 undergraduates reported the following dollar amounts of entertainment expenses last year:
a. Find the mean, median, and mode of this information.
b. What are the range and standard deviation?
c. Use the Empirical Rule to establish an interval that includes about 95% of theobservations. |
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| m110 | A sample of 36 observations is selected from a normal population. The sample mean is 21, and the population standard deviation is 5. Conduct the following test of hypothesis using the .05 significance level.
H0: µ ≤20
H1: µ >20
(a) Is this a one- or two-tailed test?
(b) What is the decision rule?
(c) What is the value of the test statistic?
(d) What is your decision regarding H0?
(e) What is the p-value? Interpret it. |
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| m111 | A sample of 36 observations is selected from a normal population. The sample mean is 49, and the population standard deviation is 5. Conduct the following test of hypothesis using the .05 significance level.
H0: µ = 50
H1: µ ≠ 50
(a) Is this a one- or two-tailed test?
(b) What is the decision rule?
(c) What is the value of the test statistic?
(d) What is your decision regarding H0?
(e) What is the p-value? Interpret it. |
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| m112 | A sample of 36 observations is selected from a normal population. The sample mean is 12, and the population standard deviation is 3. Conduct the following test of hypothesis using the .01 significance level.
H0: µ ≤10
H1: µ >10
(a) Is this a one- or two-tailed test?
(b) What is the decision rule?
(c) What is the value of the test statistic?
(d) What is your decision regarding H0?
(e) What is the p-value? Interpret it. |
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| m113 | A sample of 40 observations is selected from one population with a population standard deviation of 5. The sample mean is 102. A sample of 50 observations is selected from a second population with a population standard deviation of 6. The sample mean is 99. Conduct the following test of hypothesis using the .04 significance level.
H0: µ1 = µ2
H1: µ1 ≠ µ2
a. Is this a one-tailed or a two-tailed test?
b. State the decision rule.
c. Compute the value of the test statistic.
d. What is your decision regarding H0?
e. What is the p-value? |
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| m114 | A sample of 40 oil industry executives was selected to test a questionnaire. One question about environmental issues required a yes or no answer.
a. What is the experiment?
b. List one possible event.
c. Ten of the 40 executives responded yes. Based on these sample responses, what is the probability that an oil industry executive will respond yes?
d. What concept of probability does this illustrate?
e. Are each of the possible outcomes equally likely and mutually exclusive? |
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| m115 | A sample of 45 overweight men participated in an exercise program. At the conclusion of the program, 32 had lost weight. At the .05 significance level, can we conclude the program is effective?
a. State the null hypothesis and the alternate hypothesis.
b. State the decision rule.
c. Compute the value of the test statistic.
d. What is your decision regarding the null hypothesis? |
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| m116 | A sample of 50 funds deposited in First Federal Savings Bank’s MCA (miniature checking account) revealed the following amounts.
Use a statistical software package such as Excel or Minitab to help answer the following questions.
a. Determine the mean, median, and standard deviation.
b. Determine the first and third quartiles.
c. Develop a box plot. Are there any outliers? Do the amounts follow a symmetric distribution or are they skewed? Justify your answer.
d. Organize the distribution of funds into a frequencydistribution. |
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| m117 | A sample of 60 college students was given a special training program designed to improve their time management skills. One month after completing the course, the students were contacted and asked whether the skills learned in the program were effective. A total of 42 responded yes. At the .05 significance level, can we conclude the program is effective?
a. State the null hypothesis and the alternate hypothesis.
b. State the decision rule.
c. Compute the value of the test statistic.
d. What is your decision regarding the null hypothesis? |
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| m118 | A sample of 64 observations is selected from a normal population. The sample mean is 215, and the population standard deviation is 15. Conduct the following test of hypothesis using the .025 significance level.
H0: µ ≤220
H1: µ <220<br>
(a) Is this a one- or two-tailed test?
(b) What is the decision rule?
(c) What is the value of the test statistic?
(d) What is your decision regarding H0?
(e) What is the p-value? Interpret it. |
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| m119 | A sample of 65 observations is selected from one population with a population standard deviation of 0.75. The sample mean is 2.67. A sample of 50 observations is selected from a second population with a population standard deviation of 0.66. The sample mean is 2.59. Conduct the following test of hypothesis using the .08 significance level.
H0: µ1 = ≤µ2
H1: µ1 ≠ > µ2
a. Is this a one-tailed or a two-tailed test?
b. State the decision rule.
c. Compute the value of the test statistic.
d. What is your decision regarding H0?
e. What is the p-value? |
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| m120 | A sample of employees at a large chemical plant was asked to indicate a preference for one of three pension plans. The results are given in the following table. Does it seem that there is a relationship between the pension plan selected and the job classification of the employees? Use the .01 significancelevel. |
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| m121 | A sample of students attending Southeast Florida University is asked the number of social activities in which they participated last week. The chart below was prepared from the sample data.
a. What is the name given to this chart?
b. How many students were in the study?
c. How many students reported attending no socialactivities? |
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| m122 | A school supervisor is reviewing initial wages of former students (in $000). Samples were taken over 3 years for four different majors (accounting, administration, finance, and marketing). For each combination of major and year, three former students were sampled.
a. Here is an interaction plot of the information. What does it reveal?
b. Write out all of the pairs of null and alternative hypotheses you would apply for a two-way ANOVA.
c. Here is the statistical software output. Use the 0.05 level to check for interactions.
d. If proper, test the other hypotheses at the .05 significance level. If it is not appropriate, describe why you should not do thetests. |
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