A set of rectangles whose arcs were in proportion to class frequencies is known as? A) Polygon B) Histogram C) Ogive D) Cumulative Frequency Curve Related MCQs: The lower and upper cut-off frequencies are also called——frequencies The related facts or observations which are grouped into classes or categories are known as? The process of summarizing classified data in the form of a table is known as? The law of effect is also known as: