The mean of 100 observations is 50. If one of the observation which was 50 is replaced by 150, the resulting mean will be
(a) 50-5
(b) 51
(c) 51-5
(d) 52
Solution:
Mean =( sum of the observations )/( number of observations )
According to the question
(i) Sum of the 100 observations/ 100
= mean
Sum of the 100 observations
= 50× 100
= 5000 ——( 1 )
(ii) if one of the observation 50
replaced by 150
New Sum of the 100 observations
= 5000 – 50 + 150 [ from ( 1 ) ]
= 5100 —( 2 )
New mean = ( 2 )/ 100
= 5100/ 100
= 51 is correct
Median of the numbers 4, 4, 5, 7, 6, 7, 7, 3, 12 is
Solution:
6 is correct
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