Explaining that the deferential standard of review is appropriate because the "[the ALJ] ... sees the witnesses and hears them testify, while the Board and the reviewing court look only at cold records"
Holding that employer-employee relationship is determined by power to set wages and hours, coupled with the financial burden of the wages and receipt of the benefits of the work, as well as the absolute power to hire and fire or the power to control all the activities of the worker