NCERT Class 11 Mathematics Solutions: Chapter 15 – Statics Miscellaneous Exercise Part 1 (For CBSE, ICSE, IAS, NET, NRA 2023)
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1. The mean and variance of eight observations are , respectively. If six of the observations are , find the remaining two observations.
Answer:
Consider the remaining two observations be .
So, the observations are .
Mean,
… eq (1)
… [Using (1) ]
… eq (2)
From eq (1)
… eq (3)
From eq (2) and (3) ,
… eq (4)
Subtracting eq (4) from (2) ,
… eq (5)
So, from (1) and (5) ,
,
When
,
When
The remaining observations are .