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\textbf{A copy machine dealer has data on the number x of copy machines at each of 89 customer locations and the number y of service calls in a month at each location. Summary calculations give $$\bar{}x$$ = 8.4, $$S\_x$$ = 2.1, ȳ = 14.2, $$S\_y$$ = 3.8, and r = 0.86. What is the slope of the least squares regression line of number of service calls on number of copiers?} 
Overseas Competition->Knowledge Point->Calculation Modules
$$\beta\_1 =r \frac{S\_y}{S\_x} = 0.86 * \frac{3.8}{2.1} = 1.56$$ 