The mean of following frequency table is 50. Class Frequency 0 -20 17 20-40 f1 40-60 32 60-80 f2 80 - 100 19 Total 120 The missing frequencies are

Question

The mean of following frequency table is 50. Class Frequency 0 -20 17 20-40 f1 40-60 32 60-80 f2 80 - 100 19 Total 120 The missing frequencies are (A) 28, 24 (B) 22, 36 (C) 36, 28 (D) 35, 17

Tardigrade Admin · Accepted Answer

We have, Mid point (x) Frequency (f) fx 10 17 170 30 f1 30 f1 50 32 1600 70 f2 70 f2 90 19 1710 Total 120 30 f1+70 f2+3480 Now, barx = (1/120) Sigma fx ⇒ 50 = (1/120) × (30 f1+70 f2+3480) ⇒ 600 = 3 f1+7 f2+348 ⇒ 3 f1+7 f2=252 ldots(i) Also, f1 + f2 + 68 = 120 ⇒ f1 + f2 = 52 ldots(ii) Solving (i) and (ii), we get f1 = 28, f2 = 24

Class	Frequency
$0 - 20$	$17$
$20 - 40$	$f_{1}$
$40 - 60$	$32$
$60 - 80$	$f_{2}$
$80 - 100$	$19$
Total	$120$

Mid point $(x)$	Frequency $(f)$	$f x$
$10$	$17$	$170$
$30$	$f_{1}$	$30 f_{1}$
$50$	$32$	$1600$
$70$	$f_{2}$	$70 f_{2}$
$90$	$19$	$1710$
Total	$120$	$30 f_{1} + 70 f_{2} + 3480$

Q. The mean of following frequency table is $50$ .

Class Frequency

$0 - 20$ $17$

$20 - 40$ $f_{1}$

$40 - 60$ $32$

$60 - 80$ $f_{2}$

$80 - 100$ $19$

Total $120$

The missing frequencies are

$28$ , $24$

$22$ , $36$

$36$ , $28$

$35$ , $17$

Q. The mean of following frequency table is 50. Class Frequency 0−20 17 20−40 f1​ 40−60 32 60−80 f2​ 80−100 19 Total 120 The missing frequencies are

28, 24

22, 36

36, 28

35, 17

Q. The mean of following frequency table is $50$ .

Class Frequency

$0 - 20$ $17$

$20 - 40$ $f_{1}$

$40 - 60$ $32$

$60 - 80$ $f_{2}$

$80 - 100$ $19$

Total $120$

The missing frequencies are

$28$ , $24$

$22$ , $36$

$36$ , $28$

$35$ , $17$