(a) What is meant by a class interval in a grouped frequency distribution?
(a) What is meant by a class interval in a grouped frequency distribution?
(b) Distinguish between the lower class limit and the upper class limit of a class interval with the help of one suitable numerical example.
(c) Give two reasons why, when organising continuous data, the class intervals of a grouped frequency distribution are usually taken to be continuous and of equal width.
(d) In a grouped table, explain the relationship between the class size and the class mark, quoting the general algebraic formula that connects these two quantities.