RRB Non Technical Model Papers 9 with solutions

Question : 34 of 100

Marks: +1, -0

The mean of 15 observations is 15. If 3 is subtracted from each observation, the new mean is :

Solution:

(2) From question,

{x_1 x_2 ...+x_15}/15= 15

∴ x_1 + x_2 + ... + x_15 = 225 ... (1)

Subtracting 3 from all observations.
∴New average

={(x_1 -3 )+(x_2- 3) +...+(x_15- 3)}/15

=180/15= 12

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