Question
The class marks of a frequency distribution are 104, 114, 124, 134, 144, 154, 164. Find the class size and class intervals.
Solution
Class size = 114 – 104 = 10
The class intervals are
104 – 5 — 104 + 5, i.e., 99 – 109;
114 – 5 — 114 + 5, i.e., 109 –119;
124 – 5 — 124 + 5, i.e., 119 – 129;
134 – 5 — 134 + 5, i.e., 129 – 139;
144 – 5 —144 + 5, i.e., 139 – 149;
154 – 5 — 154 + 5, i.e„ 149 – 159;
164 – 5 — 164 + 5, i.e., 159 – 9.
