Question

Find the missing frequency from the following distribution if its mean is 15.25.
X:
10
12
14
16
18
20
F:
3
7
?
20
oc
5​

Answer 1

Step-by-step explanation:

Given frequency =120

⇒17+f1+32+f2+19=120

⇒f1+f2=52

Mean =∑fi∑xifi

⇒mean =120(10×17)+(30×f1)+(50×32)+(72×f2)+(90×19)

⇒mean =120170+30f1+1600+70f2+1710=50

⇒3f1+7f2=252

⇒3f1+7(52−f1)=252

⇒f1=28

⇒f2=24

I hope it will help you to understand