2. Missing frequency when Mean is given example
1. Find missing frequency from the following data
18,14,15,19,15,a,12,15,16 and Mean=16
Solution:
Here `18,14,15,19,15,a,12,15,16`
Here Mean `bar x = 16` and `n = 9`
`sum x = 18 + 14 + 15 + 19 + 15 + a + 12 + 15 + 16`
`=a + 124`
Mean `bar x = (sum x)/n`
`16 = (a + 124)/9`
`144 = a + 124`
`a = 144 - 124`
`a = 20`
2. Find missing frequency from the following data
`85,96,76,108,85,x,100,85,70,95` and MEAN`=88`
Solution:
Here `85,96,76,108,85,x,100,85,70,95`
Here Mean `bar x = 88` and `n = 10`
`sum x = 85 + 96 + 76 + 108 + 85 + x + 100 + 85 + 70 + 95`
`=x + 800`
Mean `bar x = (sum x)/n`
`88 = (x + 800)/10`
`880=x + 800`
`x=880 - 800`
`x=80`
This material is intended as a summary. Use your textbook for detail explanation.
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