A digital sampling oscilloscope obtained the following eye diagram while observing the characteristics of a 1-Gbps digital signal. Histograms were obtain using the built-in function of the scope at a sampling instant midway between transitions (i.e., at the maximum point of eye opening). Detailed analysis revealed that each histogram is Gaussian. One histogram has a mean value of 2.8 V and a standard deviation of 150 mV. The other has a mean of 120 mV and a standard deviation of 75 mV. Estimate the BER level when the threshold level is set at 2.0 V