Question

if xi's are the midpoints of the class intervals of a grouped data fi's then find sigma fi (xi - x)

Answer 1

Answer:

Step-by-step explanation:

Solution:

Mean (x) = Sum of all the observations/ Number of observations

x = (f1x1 + f2x2 + …..+ fnxn) / f1 + f2 +......+ fn

x = Σfixi / Σfi , Σfi = n

x = Σfixi / n

n x = Σfixi ……………(1)

Σ(fixi - x) = ( f1x1 - x) + ( f2x2 - x)+ …..+(fnxn - x)

Σ(fixi - x) = (f1x1 + f2x2 + …..+ fnxn) - (x +x +....n times)

Σ(fixi - x) = Σfixi -nx

Σ(fixi - x) = nx - nx ( From eq1)

Σ(fixi - x) = 0

HOPE THIS WILL HELP YOU....

Answer 2

Answer:

this is the answer.........