If the standard deviation of the numbers 2, 3, a and 11 is 3.5,
then which of the following is true ?
3a2 − 26 a + 55 = 0
3a2 − 32a + 84 = 0
3a2 − 34a + 91 = 0
3a2 − 23a + 44 = 0
As we learnt in
Standard Deviation -
If x1, x2...xn are n observations then square root of the arithmetic mean of
- wherein
where is mean
Option 1)
3a2 − 26 a + 55 = 0
This option is incorrect.
Option 2)
3a2 − 32a + 84 = 0
This option is correct.
Option 3)
3a2 − 34a + 91 = 0
This option is incorrect.
Option 4)
3a2 − 23a + 44 = 0
This option is incorrect.
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