In color theory, a purple is defined as any non-spectral color between violet and red (excluding violet and red themselves). The spectral colors violet and indigo are not purples according to color theory, but they are purples according to common English usage since they are between red and blue.
Apex Learning was started in 1997 by Microsoft co-founder Paul Allen on the idea that online courses and test prep, which were already succeeding in higher education, could be applied to K-12.
History and description. VALS was developed in 1978 by social scientist and consumer futurist Arnold Mitchell and his colleagues at SRI International. It was immediately embraced by advertising agencies and is currently offered as a product of SRI's consulting services division. VALS draws heavily on the work of Harvard sociologist David Riesman and psychologist Abraham Maslow.