Question

The class marks of a distribution are $62,67,72,77,82$ and $87$. Find the class-size and class-limits.

• A. Class size $=7$; Class limits $595-645,645-695,695-745,745-795,795-845$ and $845-895$
• B. Class size $=4$; Class limits $595-645,645-695,695-745,745-795,795-845$ and $845-895$
• C. Class size $=9$; Class limits $595-645,645-695,695-745,745-795,795-845$ and $845-895$
• D. None of these

Answer 1

The correct option is D None of these

Class size $=67-62=72-67=5$

$\therefore$ Class size $=5$

Class interval for first class mark is $(62-2.5=59.5)-(62+2.5=64.5)$
Similarly for the rest, intervals are $64.5-69.5,69.5-74.5,74.5-79.5,79.5-84.5$ and $84.5-89.5$

Hence, the class limits are $59.5-64.5,64.5-69.5,69.5-74.5,74.5-79.5,79.5-84.5$ and $84.5-89.5$