Question

Given the following frequency distribution with some missing frequencies. Class 10-20 20-30 30-40 40-50 50-60 0-70 70-80 Frequency 185, a, 34, 180, 136 ,b ,50 respectively .If the total frequency is 685 and 42.6, find out the missing frequencies. a and b Options O 62,77
O 32, 17
O 77, 23
O 23, 57​

Answer 1

Answer:

I don't know

Step-by-step explanation:

please understand

Answer 2

Given:

Class           - 10-20    20-30   30-40   40-50   50-60   60-70   70-80

Frequency  -  185         a           34         180        136        b           50

To find: a and b

Formula to be used:

Median=42.6

$Median=l+\frac{\frac{n}{2} -c.f}{f} *h$

Step-by-step explanation:

Step 1 of 3

class                  f                     cf  

10-20              185                  185

20-30              a                     185+a

30-40              34                   219+a

40-50             180                  399+a

50-60             136                  535+a    

60-70               b                    535+a+b

70-80             50                    585+a+b

585+a+b=685

a+b=100

Step 2 of 3

Median=42.6

$Median=l+\frac{\frac{n}{2} -c.f}{f} *h$

l=40

n=685

c.f=219+a

f=180

h=10

$Median=40+\frac{\frac{685}{2} -(219+a)}{180} *10\\\\42.6=40+\frac{342.5-219-a}{18} \\\\2.6=\frac{123.5-a}{18} \\\\46.8=123.5-a\\\\a=76.7$

$a+b=100\\\\b=100-b\\\\b=100-76.7\\\\b=23.3$

a=76.7

b=23.3