| [removed] | Do not reject H0 the explanatory variables are not jointly significant in explaining y. 2. Akiko Hamaguchi is a manager at a small sushi restaurant in Phoenix, Arizona. Akiko is concerned that the weak economic environment has hampered foot traffic in her area, thus causing a dramatic decline in sales. In order to offset the decline in sales, she has pursued a strong advertising campaign. She believes advertising expenditures have a positive influence on sales. To support her claim, Akiko assumes the linear regression model as Sales = β0 + β1 Advertising + β2 Unemployment + ε. A portion of the regression results is shown in the accompanying table. Use Table 2 and Table 4. |
| ANOVA | df | SS | MS | F | Significance F | | Regression | 2 | 88.2574 | 44.1287 | 8.387 | 0.0040 | | Residual | 14 | 73.6638 | 5.2617 | | | Total | 16 | 161.9212 | | |
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| | Coefficients | Standard Error | t Stat | p-value | Lower 95% | Upper 95% | | Intercept | 33.1260 | 6.9910 | 4.7384 | 0.0003 | 18.1300 | 48.12 | | Advertising | 0.0287 | 0.0080 | 3.5875 | 0.0029 | 0.0100 | 0.05 | | Unemployment | −0.6758 | 0.3459 | −1.9537 | 0.0710 | −1.4200 | 0.0700 |
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| a-1. | Choose the appropriate hypotheses to test whether the explanatory variables jointly influence sales. | | | | | | | [removed] | H0: β1 = β2 = 0; HA: At least one β j < 0 | | [removed] | H0: β1 = β2 = 0; HA: At least one β j > 0 | | [removed] | H0: β1 = β2 = 0; HA: At least one β j ≠ 0 |
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| a-2. | Find the value of the appropriate test statistic. (Round your answer to 3 decimal places.) |
| a-3. | At the 5% significance level, do the explanatory variables jointly influence sales? | | | | | | | [removed] | Yes, since the F-test is significant. | | [removed] | Yes, since all t-tests are significant. | | [removed] | Both answers are correct. |
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| b-1. | Choose the hypotheses to test whether the unemployment rate is negatively related with sales. | | | | | | | [removed] | H0: β2 = 0; HA: β2 ≠ 0 | | [removed] | H0: β2 ≤ 0; HA: β2 > 0 | | [removed] | H0: β2 ≥ 0; HA: β2 < 0 |
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| b-2. | Find the p-value. (Round your answer to 4 decimal places.) |
| b-3. | At the 1% significance level, what is the conclusion to the test? | | | | | | | [removed] | Do not reject H0 the unemployment rate and sales are not negatively related. | | [removed] | Do not reject H0 the unemployment rate and sales are negatively related. | | [removed] | Do not reject H0 the unemployment rate and sales are related. | | [removed] | Do not reject H0 the unemployment rate and sales are not related. |
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| c-1. | Choose the appropriate hypotheses to test whether advertising expenditures are positively related to sales. | | | | | | | [removed] | H0: β1 = 0; HA: β1 ≠ 0 | | [removed] | H0: β1 ≥ 0; HA: β1 < 0 | | [removed] | H0: β1 ≤ 0; HA: β1 > 0 |
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| c-2. | Find the p-value. (Round your answer to 4 decimal places.) |
| c-3. | At the 1% significance level, what is the conclusion to the test? | | | | | | | [removed] | Reject H0 advertising expenditures and sales are positively related. | | [removed] | Do not reject H0 advertising expenditures and sales are not positively related. | | [removed] | Do not reject H0 advertising expenditures and sales are positively related. | | [removed] | Reject H0 advertising expenditures and sales are not positively related. |
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For a sample of 20 New England cities, a sociologist studies the crime rate in each city (crimes per 100,000 residents) as a function of its poverty rate (in %) and its median income (in $1,000s). A portion of the regression results are as follows. Use Table 2 and Table 4. |
| ANOVA | df | SS | MS | F | Significance F | | Regression | 2 | 2,576.7 | 1,288.4 | ? | 0.8163 | | Residual | 17 | 106,595.19 | 6,270.31 | | | Total | 19 | 109,171.88 | | |
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| | Coefficients | Standard Error | t Stat | p-value | Lower 95% | Upper 95% | | Intercept | 800.10 | 126.6195 | 6.3189 | 0.0000 | 532.95 | 1,067.24 | | Poverty | 0.5779 | 6.3784 | 0.0906 | 0.9289 | −12.88 | 14.04 | | Income | −10.1429 | 16.1955 | −0.6263 | 0.5395 | −44.31 | 24.03 |
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| a. | Specify the sample regression equation. (Negative values should be indicated by a minus sign. Report your answers to 4 decimal places.) |
=[removed] + [removed] Poverty + [removed] Income |
| b-1. | Choose the appropriate hypotheses to test whether the poverty rate and the crime rate are linearly related. | | | | | | | [removed] | H0: β1 ≥ 0; HA: β1 < 0 | | [removed] | H0: β1 ≤ 0; HA: β1 > 0 | | [removed] | H0: β1 = 0; HA: β1 ≠ 0 |
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| b-2. | At the 5% significance level, what is the conclusion to the hypothesis test? | | | | | | | [removed] | Do not reject H0 the poverty rate and the crime rate are not linearly related. | | [removed] | Reject H0 the poverty rate and the crime rate are linearly related. | | [removed] | Do not reject H0 the poverty rate and the crime rate are linearly related. | | [removed] | Reject H0 the poverty rate and the crime rate are not linearly related. |
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| c-1. | Construct a 95% confidence interval for the slope coefficient of income. (Negative values should be indicated by a minus sign. Round your intermediate calculations to 4 decimal places, "tα/2,df" value to 3 decimal places and final answers to 2 decimal places.) |
| Confidence interval | [removed] to [removed] |
| c-2. | Using the confidence interval, determine whether income is significant in explaining the crime rate at the 5% significance level. | | | | | | | [removed] | Income is significant in explaining the crime rate, since its slope coefficient does not significantly differ from zero. | | [removed] | Income is not significant in explaining the crime rate, since its slope coefficient does not significantly differ from zero. | | [removed] | Income is significant in explaining the crime rate, since its slope coefficient significantly differs from zero. | | [removed] | Income is not significant in explaining the crime rate, since its slope coefficient significantly differs from zero. |
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| d-1. | Choose the appropriate hypotheses to determine whether the poverty rate and income are jointly significant in explaining the crime rate. | | | | | | | [removed] | H0: β1 = β2 = 0; HA: At least one β j < 0 | | [removed] | H0: β1 = β2 = 0; HA: At least one β j ≠ 0 | | [removed] | H0: β1 = β2 = 0; HA: At least one β j > 0 |
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| d-2. | At the 5% significance level, are the poverty rate and income jointly significant in explaining the crime rate? | | | | | | | [removed] | No, since the null hypothesis is not rejected. | | [removed] | Yes, since the null hypothesis is rejected. | | [removed] | No, since the null hypothesis is rejected. | | [removed] | Yes, since the null hypothesis is not rejected. |
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