ECO220Y1 Lecture Notes - Lecture 3: Null Hypothesis, Type I And Type Ii Errors, Confidence Interval
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*** Please see p. 2 for Question 2 ***
Question 2 (7 points)
The following Excel output shows the outcome of a linear regression of individuals%u2019 wage per hour (in dollars) on the number of years they attended school (in years).
SUMMARY OUTPUT | ||||||||
Regression Statistics | ||||||||
Multiple R | 0.381932619 | |||||||
R Square | 0.145872525 | |||||||
Adjusted R Square | 0.144267022 | |||||||
Standard Error | 4.753758428 | |||||||
Observations | 534 | |||||||
ANOVA | ||||||||
df | SS | MS | F | Significance F | ||||
Regression | 1 | 2053.22554 | 2053.22554 | 90.8578469 | 5.45998E-20 | |||
Residual | 532 | 12022.25261 | 22.59821919 | |||||
Total | 533 | 14075.47815 | ||||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | Upper 95.0% | ||
Intercept | -0.745942699 | 1.045403804 | -0.71354504 | 0.475821452 | -2.799566599 | 1.307681201 | 1.307681201 | |
Years of School | 0.750448943 | 0.078729942 | 9.531938255 | 0.000545998 | 0.595789385 | 0.9051085 | 0.9051085 |
Part (a) (1 point)
What is the value of the estimated slope %u201Cb%u201D?
Part (b) (2 points)
Interpret the estimated value of the slope (i.e., explain what the number means in this regression).
Part (c) (1 point)
Is the estimate of the slope statistically significant? Please answer %u201Cyes%u201D or %u201Cno%u201D and explain how you can tell.
Part (d) (2 points)
Explain why we want to be able to reject the null hypothesis H0: %u03B2 = 0.
Part (e) (1 point)
How much of the total variation in wages can be explained by individuals%u2019 education?
1. You are given only three quarterly seasonal indices and quarterly seasonally adjusted data for the entire year. What is the raw data value for Q4? Raw data is not adjusted for seasonality.
Quarter Seasonal Index Seasonally Adjusted Data
Q1 .80 295
Q2 .85 299
Q3 1.15 270
Q4 --- 271
2. One model of exponential smoothing will provide almost the same forecast as a liner trend method. What are linear trend intercept and slope counterparts for exponential smoothing?
A. Alpha and Delta
B. Delta and Gamma
C. Alpha and Gamma
D. Standard Deviation and Mean
3. When performing correlation analysis what is the null hypothesis? What measure in Minitab is used to test it and to be 95% confident in the significance of correlation coefficient.
A. Ho: r = .05 p < .5
B. Ho: r = 0 p >.05
C. Ho: r ? 0 p?.05
D. Ho: r = 0 p?.05
In decomposition what does the cycle factor (CF) of .80 represent for a monthly forecast estimate of a Y variable? |
A. The estimated value is 80% of the average monthly seasonal estimate.
B. The estimate is .80 of the forecasted Y trend value.
C. The estimated value is .80 of the historical average CMA values.
D. The estimated value has 20% more variation than the average historical Y data values.
5. A Wendy's franchise owner notes that the sales per store has fallen below the stated national Wendy's outlet average of $1,368,000. He asserts a change has occurred that reduced the fast food eating habits of Americans. What is his hypothesis (H1) and what type of test for significance must be applied? |
A. H1: u ? $1,368,000 A one-tailed t-test to the left.
B. H1: u = $1,368,000 A two-tailed t-test.
C. H1: u < $1,368,000 A one-tailed t-test to the left.
D. H1: p < $1,368,000 A one-tailed test to the right
A. The rejection region and the t-table value generally gets smaller for sample size below 31. |
A. Yes. The data are significantly correlated through the 12th lag. C. No. Only the 12 lag period is not correlated. D. You cannot tell since the number of sample observations is not provided. E. The p-value is above .05 so the data is correlated. |
A. Type 2 error |
A. Yes. They move in the same direction as statistical significance. |
A. The weight cannot be calculated since the data observation is not given. |
A. Yes. The correlation coefficient is .873 that is greater than .05. |
A. Yes, since the residuals randomly vary in magnitude. |
A. -101.0 |
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