The mean of 25 observations is 36. If the mean of first 13 observations is 32 and that of the last 13 observations is 39, find the 13th observation.

Asked by Topperlearning User | 6th Nov, 2017, 01:24: PM

Expert Answer:

begin mathsize 12px style Mean space of space first space 13 space observations equals 32
rightwards double arrow Sum space of space first space 13 space observations equals 32 cross times 13 equals 416
Mean space of space last space 13 space observations equals 39
rightwards double arrow Sum space of space last space 13 space observations equals 39 cross times 13 equals 507
Mean space of space 25 space observations equals 36
rightwards double arrow Sum space of space 25 space observations equals 36 cross times 25 equals 900
Hence comma space 13 to the power of th space observation
equals Sum space of space first space 13 space observation plus Sum space of space last space 13 space observation
space space space space space minus Sum space of space 25 space observations
equals 416 plus 507 minus 900
equals 23
Thus comma space the space 13 to the power of th space observation space is space 23.
end style

Answered by  | 6th Nov, 2017, 03:24: PM

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