Which of the following are normal equations to fit a straight line trend y = a + bx by the method of least squares? Option 1: y = a + x + b x^2, xy = a + x + b x^2 Option 2: y = na + b x, xy = a x + b x^2 Option 3: xy = na + b x, xy = na + b x^2 Option 4: x = na + b y^2, y = a x + b y^2

The answer is 'y = na + b x, xy = a x + b x^2'. View full solution:

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Which of the following are normal equations to fit a straight line trend y = a + bx by the method of least squares?

$\sum y = a + \sum x + b \sum x^2$ , $\sum xy = a + \sum x + b \sum x^2$

$\sum y = na + b \sum x$ , $\sum xy = a \sum x + b \sum x^2$

$\sum xy = na + b \sum x$ , $\sum xy = na + b \sum x^2$

$\sum x = na + b \sum y^2$ , $\sum y = a \sum x + b \sum y^2$

✅ Correct Option: 2

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