The mean of a set of 30 observations is 75. If each observation is multiplied by a non-zero number λ and then each of them is decreased by 25, their mean remains the same. Then λ is equal to :
As we learned
ARITHMETIC Mean -
For the values x1, x2, ....xn of the variant x the arithmetic mean is given by
in case of discrete data.
-
The new mean =
Also we have
Option 1)
Option 2)
Option 3)
Option 4)
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