Does Online Teaching Help or Hinder Student Learning? to Help

Does online teaching help or hinder student learning? To help answer this question, a statistics teacher decided to teach his three sections of a particular class using three different teaching
Models - a traditional face-to-face section, a completely online section, and a hybrid or blended
Section that incorporated both a face-to-face and online component in the section. Students were
Randomly assigned to the different sections, taught identical information using the different
Teaching formats, and given identical examinations to measure student learning. The goal was to
Identify if the teaching method used affected student learning performance. Identify the data
Collection method used in this study.

A) data from a designed experiment
B) data collected observationally
C) data from a published source