"In day-to-day life, theory means an unsubstantiated statement, an educated guess.
In science however, theory refers to a broad overarching explanation of many related phenomena.
In the natural and behavioral sciences, a theory is built up out of hypotheses that are very strongly supported by empirical evidence."
~ Annemarie Zand Scholten, Assistant Professor, Economics and Business, University of Amsterdam
Online Quantitative Methods Course on Coursera
