Electrospray time-of-flight (tof) mass spectrometry was used to analyze the eluate from a high-performance liquid chromatography (hplc) separation.
the mass spectrum of one chromatographic peak, containing a protein of unknown molecular mass, displays mhnn peaks at m/z = 3919.282, 3658.042, 3429.481, 3227.787, 3048.519, and 2888.112.

find the average molecular mass (m) of the neutral protein and its standard deviation.