Question

For the following frequency table, Find the number of telephone calls received at an exchange per interval for $250$ successive one-minute intervals.

No. of calls ($x$)	$0$	$1$	$2$	$3$	$4$	$5$	$6$
No. of intervals ($f$)	$15$	$24$	$29$	$46$	$54$	$43$	$39$

Answer 1

Answer:-

No. of calls (x)	No. of intervals (f)	fx
0	15	0
1	24	24
2	29	58
3	46	138
4	54	216
5	43	215
6	39	234

$\Sigma f=15+24+29+46+54+43+39=250$

$\Sigma fx=0+24+58+138+216+215+234=885$

$\left(\overline{x}\right)=\frac{\Sigma fx}{\Sigma f}=\frac{885}{250}=3.54$

The number of telephone calls received at an exchange per interval for $250$ successive one-minute intervals is $3.54$.