9. (а) Consider the data set of (х, у) рairs below. {(1, 2), (1, 4), (2, 4), (2, 6), (3, 6), (3, 8), (4, 8), (4, 10), (5, 10), (5, 12), (6, 12), (6, 14), (7, 14), (7, 16), (8, 16), (8, 18), (9, 18), (9, 20), (10, 20), (10, 22)}

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9. (a) Consider the data set of (x, y) pairs below.
{(1, 2), (1, 4), (2, 4), (2, 6), (3, 6), (3, 8), (4, 8), (4, 10), (5, 10), (5, 12), (6, 12),
(6, 14), (7, 14), (7, 16), (8, 16), (8, 18), (9, 18), (9, 20), (10, 20), (10, 22)}
The least squares line (i.e., the regression line) for this set is
(i) y = x + 1
(ii) y = -x+4
(iii) y = 2x +1
(iv) y = 3x+2
Visually compare the plots below for parts (b) and (c).
(1)
(ii)
(ii)
(b) If a least squares line was determined for each (x, y) plot, the variances (s²) associated to them would
be ordered from smallest to largest (where s, s, and s; are the variances corresponding to, respectively,
plot (i), plot (ii), and plot (iii)) as
(i) < s < s?
(ii) s? < s < si
(iii) s? < si < s
(iv) si < s < s?
(c) Relative to plots (ii) and (ii), the linear relationship between x and y in plot (i) appears to be
(i) strong negative
(ii) strong positive
(iii) weak negative
(iv) moderate positive
10
Transcribed Image Text:9. (a) Consider the data set of (x, y) pairs below. {(1, 2), (1, 4), (2, 4), (2, 6), (3, 6), (3, 8), (4, 8), (4, 10), (5, 10), (5, 12), (6, 12), (6, 14), (7, 14), (7, 16), (8, 16), (8, 18), (9, 18), (9, 20), (10, 20), (10, 22)} The least squares line (i.e., the regression line) for this set is (i) y = x + 1 (ii) y = -x+4 (iii) y = 2x +1 (iv) y = 3x+2 Visually compare the plots below for parts (b) and (c). (1) (ii) (ii) (b) If a least squares line was determined for each (x, y) plot, the variances (s²) associated to them would be ordered from smallest to largest (where s, s, and s; are the variances corresponding to, respectively, plot (i), plot (ii), and plot (iii)) as (i) < s < s? (ii) s? < s < si (iii) s? < si < s (iv) si < s < s? (c) Relative to plots (ii) and (ii), the linear relationship between x and y in plot (i) appears to be (i) strong negative (ii) strong positive (iii) weak negative (iv) moderate positive 10
Expert Solution
curve fitting

method of least square: This method is a form of mathematical regression analysis used to determine the line of best fit for a set of data.

  • The least-squares method is a statistical procedure to find the best fit for a set of data by minimizing the sum of residuals of points from the plotted curve.
  • The fitted line is used to predict the behavior of dependent variables.

 

calculation

1. Sum of X=110

   Sum of Y+

X¯=5.5, Y¯=12

X-X¯ Y-Y¯ (x-X¯)2 (X-X¯) x (Y-Y¯)2
-4.5 -10 20.25 45
-4.5 -8 20.25 36
-3.5 -8 12.25 28
-3.5 -6 12.25 21
-2.5 -6 6.25 15
-2.5 -4 6.25 10
-1.5 -4 2.25 6
-1.5 -2 2.25 3
-0.5 -2 0.25 1
-.05 0 0.25 0
0.5 0 0.25 0
0.5 2 0.25 1
1.5 2 2.25 3
1.5 4 2.25 6
2.5 4 6.25 10
2.5 6 6.25 15
3.5 6 12.25 21
3.5 8 12.25 28
4.5 8 20.25 36
4.5 10 20.25 45
total   165 330

regression equation:  Y^=bX+a     b=(X-X¯) x (Y-Y)¯(X-X¯)2=330165=2     a=Y¯-bX¯=12-(2*5.5)=1estimated equation is:    y^=2X+1

Hence option 3 is correct.

    

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