Consider the following earning regression model .
EARNINGS= β₁+β₂S+β₃ EXP + μ
a. Holding other factors constant, the OLS estimator β₃ is more accurate if
b. there is less variation (lower mean square deviation) in the sample of EXP.
c. S and EXP are more correlated.
d. the variance of u is higher.
e. there is more variation (higher mean square deviation) in the sample of S.