1. ## mean calculation (advance type)

'"the mean of 200items is 50, later it was discovered that two of the items used to derived the mean i.e 92 and 8 were actually 192 and 88. what is the corrected mean after replacing the right items (192and 88)?". have tried all i could but could not arrived at the answer, what is it am missing here i mean right procedure, contributions will be highly appreciated.

this is for practice purpose. thanks

2. ## Re: mean calculation (advance type)

Is this a problem in advanced probability or in basic algebra?

Let S be the sum of all items except for the two items in question. Then $\frac{S+92+8}{200}=50$. From here you can find $S$ and calculate $\frac{S+192+88}{200}$. Actually, $\frac{S+192+88}{200}=\frac{S+92+8}{200}+\frac{180} {200}=50.9$.