Bell Corp. used the following regression model to determine if the forecasts over the last 20 years were biased: St = a0 + a1Ft - 1 + mt, where St is the spot rate of the Canadian dollar in year t and Ft - 1 is the forward rate of the Canadian dollar in year t - 1. Regression produces coefficients of a0 = 0 and a1 = .30. Based on the output from regression, Bell Corp. would likely believe that its past forecasts have ____ the realized spot rate. Group of answer choices underestimated overestimated estimated correctly Cannot tell