If the class marks (mid-points) in a grouped frequency distribution of weights (in kgs) of a group of students are 75,84,93,102,111,120,129 Find out

(i) Width of the class/size of the class interval.

(ii) The class limits assuming that weights are measured to the nearer warns.

(iii) The class boundaries.

(i) Width of the Class = Difference of Two Consecutive Mid-Values = 84 - 75 or 93 - 84 = 9

(ii) The class limits are 71-79, 80-88, 89-97, 98-106,107-115,116-124,125-133

(iii) The class boundaries are

(a) 75 --9/2, 75+9/2 i.e., 70.5-79.5

(b) 84–9/2,84 +9/2 i.e., 79.5-88.5

© 93 --9/2,93 + 9/2 i.e., 88.5-97.5

(d) 102-- 9/2, 102 + 9/2 i.e., 97.5-106.5

(e) 111-- 9/2,111 +9/2 i.e., 106.5-115.5

(f) 120–9/2.120 + 9/2 i.e., 11.5-124.5

(g) 129-- 9/2,129 + 9/2 i.e., 124.5-133.5