Correlation and Regression Questions and Answers

Six sales representatives made the following numbers of calls to potential customers: 7, 6, 8, 6, 1, 2, with corresponding sales turnovers ($1000): 11, 10, 14, 12, 8, 9. What is the product moment correlation coefficient between number of calls and sales turnover, to 2 decimal places?

Six sales representatives made calls (7, 6, 8, 6, 1, 2) with corresponding sales turnovers ($1000): 11, 10, 14, 12, 8, 9. Using the least squares regression equation of turnover on number of calls, what is the gradient (slope) of the regression line, to 3 decimal places?

For a data set with D: 0, 5, 10, 15, 20, 25, 30, 35 and corresponding M: 90, 82, 56, 68, 58, 46, 30, 20, what is the product moment correlation coefficient r, to 3 decimal places?

For a data set with D: 0, 5, 10, 15, 20, 25, 30, 35 and corresponding M: 90, 82, 56, 68, 58, 46, 30, 20, the product moment correlation coefficient works out to r is approximately -0.957. Which statement best describes this correlation?

A social scientist recorded ARD rate ($X\%$) and divorce rate ($Y\%$) over 6 periods, with $n=6$, $\sum X=684$, $\sum Y=64$, $\sum X^2=92312$, $\sum Y^2=926$, $\sum XY=9106$. What is the product moment correlation coefficient, to 3 decimal places?

A social scientist recorded ARD rate ($X\%$) and divorce rate ($Y\%$) over 6 periods, with $n=6$, $\sum X=684$, $\sum Y=64$, $\sum X^2=92312$, $\sum Y^2=926$, $\sum XY=9106$. What is the gradient of the regression line of $y$ upon $x$, to 3 decimal places?