Question 454906
An advertising firm wishes to demonstrate to its clients the effectiveness of the advertising campaigns it has conducted. The following bivariate data on twelve recent campaigns, including the cost of each campaign (denoted by x, in millions of dollars) and the resulting percentage increase in sales (denoted by y) following the campaign, were presented by the firm. The least-squares regression line for these data has a slope of approximately 0.16. 
Campaign cost(x)

1.56 
2.31 
3.88 
2.93 
2.14 
3.21 
1.78 
1.28 
3.80 
3.01 
3.51 
2.04

percentage increase in sales (y) 
6.63 
6.67
6.97
6.64
6.74
6.44
6.26
6.38
6.71
6.88
6.85
6.43 

What is the value of the y-intercept of the least-squares regression line for these data? 
What is the value of the sample correlation for these data? 

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Most texts recommend a calculator or a software program,
such as EXCEL.
I entered the data into my TI-84 and ran a Linear Regression
program and got f(x) = 0.1622x + 6.208
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The y-intercept is 6.208
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The value of the sample correlation is r = 0.66298
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Cheers,
Stan H.