Repeat problem 1 for the data of problem 3.
Problem 1
Carry out an F test for a linear relationship in problem 2. Compare your results with those of the t test.
Problem 2
Recently, research efforts have focused on the problem of predicting a manufacturer's market share by using information on the quality of its product. Suppose that the following data are available on market share, in percentage (Y ), and product quality, on a scale of 0 to 100, determined by an objective evaluation procedure (X ):
X: 27 39 73 66 33 43 47 55 60 68 70 75 82
Y: 2 3 10 9 4 6 5 8 7 9 10 13 12
Estimate the simple linear regression relationship between market share and product quality rating.
Problem 3
For the data given below, regress one variable on the other. Is there an implication of causality, or are both variables affected by a third?
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Sample of annual transactions ($ millions)
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Year
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Credit card
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Online debit card
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2002
|
156
|
211
|
|
2003
|
204
|
280
|
|
2004
|
279
|
386
|
|
2005
|
472
|
551
|
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2006
|
822
|
684
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2007
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1,213
|
905
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