Consistency of an estimator can be checked by comparing____________?

A. Cheapest method
B. Existing Sources
C. Primary
D. Secondary

A. SD(X)−SD(Y)
B. SD(X)+SD(Y)
C. SD(X)+SD(Y)−−−−−−−−−−−−−−√
D. Var(X)+Var(Y)−−−−−−−−−−−−−−−√
18) If Y=−8X − 5 and SD of X is 3, then SD of Y is

A. Population data
B. Sample data
C. Test statistics
D. None of these