Question

the mean of the following frequency table is 50. the frequencies f1 and f2 in class 20-40 and 60-80 are missing. find the missing frequencies. class: 0-20,20-40,40-60,60-80,80-100. frequency: 17,f1,32,f2,19,total-120

Answer 1

Mean A=50,

h=20

We have:

sigma fi=120 (given)

⇒ 68+fi+f2=120

⇒ fi+f2=52 .....(1)

⇒Now, Mean=50

⇒X bar=a +h(sigma fiui divided by sigma fi)

⇒50=50+20*(4-fi+f2 divided by 120)

⇒50=50+4-fi+f2 divided by 6

⇒0=4-fi=f2 divided by 6

⇒fi-f2=4.....(2)

⇒From (1) and (2),

fi-f2=52

f1-f2=4

---------------------

2fi=56

⇒fi=28

⇒Substituting fi=28 in equation(1),

⇒28+f2=52

⇒f2=24

So the missing frequencies fi is 28 and f2 is 24

Hope it helps you :D!!

Answer 2

Answer:

here ,F1=28

F2=24

hope this will be helpful..................