The mean of 100 iterms was found to be 64. Later on it was discovered that two items were misread as 26 and 9 instead of 36 and 90 respectively. Find the correct mean.

Explanation

Mean of 100 items, as calculated = 64
Sum of 100 items, as calculated = `( 64 xx 100) = 6400`
Correct sum of 100 items
= ( 6400 -( sum of wrong items ) +( sum of correct iterms) )
= { 6400 -(26 +9) +(36 +90)}
= ( 6400 -35 +126) = ( 6526 -35) = 6491.
Correct mean =` ((6491)/100) = 64.91 `