alleryIf two regression equations are 3x + 2y = 26 and 6x + y = 31, the means xbar, ybar are
A(3, 8)
B(5, 5)
C(4, 7)
D(7, 4)
Answer & Solution
Correct answer: C. (4, 7)
1. Both lines pass through (xbar, ybar); solve the system.
2. Multiply second equation by 2: 12x + 2y = 62.
3. Subtract first equation: (12x + 2y) - (3x + 2y) = 62 - 26, so 9x = 36 and x = 4.
4. Substitute into 6x + y = 31: 24 + y = 31, y = 7.
_Source: ICAI BoS Foundation Paper 3, Ch 17 'Regression', p.10_
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