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# Regression analysis and Time series

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Nancy Giggles has not been doing well on statistics examinations. She decides to sample 12 of her friends to determine the number of hours spent studying for Test 3 and the score out of 100 received on that test. The results:

Test 4 Score
Hours of study
47 7
55 10
87 39
98 43
37 2
71 12
100 51
98 48
85 23
82 26
56 7
78 14

(i) Find the equation of the regression line using the least square technique. Interpret the meanings conveyed by the regression equation.
(ii) Compute the correlation coefficient and the coefficient of Determination. Interpret these values.

2. David Gallano, a wine merchant, has selected opinions on grape wine quality from a random sample of his customers. The customers tasted wine made from grapes grown in three regions of the country. The customers rated wine quality on a scale of 1 (best) to 4 (worst). The sample data looks like:

Customer Quality Rating of Wine by Grape-growing region
Quality Rating
Growing Region
I Growing Region
II Growing Region
III Row Total
1 15 10 6 31
2 7 13 12 32
3 11 12 8 31
4 3 8 15 26
Column Total
36 43 41 120

David wants to know whether quality ratings are independent of the grape-growing region. Can you conclude at a 95% confidence that the quality rating is independent of the growing region?

3. Ex. 15- Chapter 14 from your textbook
(a) Choose one category of consumer credit and plot it. (b) Describe the trend (if any) and discuss possible causes. (c) Fit a trend model of your choice. (d) Make a forecast for 2004, using a trend model of your choice. Note: Revolving credit is mostly credit card and home equity loans, while non-revolving credit is for a specific purchase such as a car. Consumer

Consumer Credit Outstanding, 1994-2003 (\$ billions)
Year Total Revolving Nonrevolving
1995 1,141 443 698
1996 1,242 499 743
1997 1,305 522 783
1998 1,400 563 837
1999 1,513 590 922
2000 1,686 659 1,027
2001 1,822 704 1,118
2002 1,903 828 1,186
2003 2,002 745 1,257

https://brainmass.com/statistics/regression-analysis/regression-analysis-and-time-series-218326

#### Solution Summary

The solution provides step by step method for the calculation of model for time series and linear regression . Formula for the calculation and Interpretations of the results are also included.

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## Scatter Plot Time Series

Part A Scatter plot

1) Does it look linear?

Part B Regression Analysis

1.) What is the regression equation?

2.) What are the predictions for 2006 and 2007?

Part C Working file

1.) Attach the document with the calculations

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INSTRUCTIONS

MegaStat Users
A. Create a scatterplot in MegaStat for t vs. Sales (select Markers and Lines).

B. Run the regression analysis making predictions for 2006 and 2007.
+ Specify Durbin-Watson calculation.

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Non MegaStat Users
A. Create a XY (Scatter) in Chart for t vs. Sales

B. Run the regression analysis to make predictions for 2006 and 2007.
+ X = t
+ Y = Sales
+ Create a regression equation
+ Substitute X = 15 and calculate predicted Sales value.
+ Substitute X = 16 and calculate predicted Sales value.

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