A positive E cell value indicates that the electrochemical reaction is favorable due to the relationship between Gibbs free energy and cell potential. The equation ΔG^0 = -nFE^0_cell shows that a negative free energy change corresponds to a positive E cell, making the reaction plausible. This is rooted in thermodynamic conventions where ΔG^0 < 0 suggests that the reaction will proceed spontaneously. Additionally, the relationship ΔG^0 = -RT lnK implies that a negative ΔG^0 leads to a reaction quotient K greater than 1, indicating product formation is favored. Understanding these conventions clarifies the implications of electrode potentials in electrochemical cells.