A pair of variables, x and y, have a correlation coefficient of -0.775. Which of the following statements is true ?
a.variation of x explains about 60.1% of the variation of y
b.variation of x explains about 77.5% of the variation of y
c.variation of x cannot explain about 60.1% of the variation of y
d.variation of x explains 39.94% of the variation of y
