In an area of the Great Plains, records were kept on the relationship between the rainfall (in inches) and the yield of wheat (bushels per acre). Calculate the linear correlation coefficient.

x:11.2,9.5,14.1,13.2,19.15,11,7.7,16.3,16.7

y:52.5,48.2,60.8,61,844,51.2,33.9,78,80.8

a0.998

b0.900

c0.899

d0.981