A rock specimen from a particular area is randomly selected and weighed two different times. Let W denote the actual weight and X1 and X2 the two measured weights. Then X1 W E1 and X2 W E2, where E1 and E2 are the two measurement errors. Suppose that the Ei s are independent of one another and of W and that

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a. Express r, the correlation coefficient between the two measured weights X1 and X2, in terms of , the variance of actual weight, and , the variance of measured weight.

b. Compute r when sW 1 kg and sE .01 kg.