Question

If the mean of the following frequency distribution is 188. Find the arising frequency F1 and F2

Answer 1

Answer:

f1=15,f2=30

Step-by-step explanation:

Given : Mean = 188

C.L. fi​ xi​ fi​xi​

0 - 80              20 40              800

80 - 160 25 120 3000

160 - 240 f1​ 200 200 f1​

240 - 320 f2​ 280 280 f2​

320 - 400 10 360 3600

Total ∑fi​=100=55+f1​+f2​  ∑xi​fi​=7400+200f1​+2800f2​

x=∑fi​∑fi​xi​​⇒188=1007400+200f1​+280f2​​

18800=7400+200f1​+280f2​⇒18800−7400=200f1​+280f2​

11400=200f1​+280f2​⇒1140=20f1​+28f2​

285=5f1​+7f2​............(i)

Also f1​+f2​+55=100⇒f1​+f2​=100−55⇒f1​+f2​=45....................(ii)

Solving equation (i) and (ii) f1​=15,f2​=30

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