Question

Match the two columns.
$\begin{array}{cc}Column-I& Column-II\\ \text{(A) The class mark of the class interval}& \text{(p) 13}\\ 145-150is:& \\ \text{(B) In a frequency distribution, the mid – value of a}& \text{(q) 110}\\ \text{class is 10 and width of each class is 6. The upper}& \\ \text{limit of the class is:}& \\ \text{(C) The mean of eight numbers is 40. If one}& \text{(r) 22.5 – 27.5}\\ \text{number is excluded, their mean becomes 30.}& \\ \text{The excluded number is:}& \\ \text{(D) The class marks of a frequency distribution are}& \left(s\right)147.5\\ 15,20,25,30,\dots \dots \text{The class corresponding to the class}& \\ \text{mark 25 is:}& \end{array}$

Answer 1

$\left(A\right)\to s;\left(B\right)\to p;\left(C\right)\to q;\left(D\right)\to r$

(A) Classmark
$=\frac{145+150}{2}=\frac{295}{2}=147.5$.

(B) Let the upper limit = x
Lower limit = y
$\therefore x-y=6$ and $\frac{x+y}{2}=10\Rightarrow x+y=20$
On solving both the equations, we get x = 13 and y = 7

(C) Sum of the 8 observation $=40\times 8=320$
Sum of the 7 observation $=30\times 7=210$
Excluded observation is 320 - 210 = 110

(D) Class width = 20 - 15 = 5
Class mark = 25
$\therefore$ Required class,
$(25-\frac{5}{2})-(25+\frac{5}{2})\Rightarrow 22.5-27.5$