Question

The following is data for the first and second Quiz scores for 8 students in a class. First Quiz (Q1) Second Quiz (Q2) | 12 | 11 17 13 1917 2019 22 18 26 25 27 24

Answer 1

	First (X)	Second (Y)	X * Y	X2	Y2
	11	9	99	121	81
	12	11	132	144	121
	17	13	221	289	169
	19	17	323	361	289
	20	19	380	400	361
	22	18	396	484	324
	26	25	650	676	625
	27	24	648	729	576
Total	154	136	2849	3204	2546

Scatter Plot 5 10 15 20 25 30

Equation of regression line is Ŷ = a + bX
b = ( n \Sigma XY - \Sigma X \Sigma Y) / ( n\Sigma X^{2} - (\Sigma X)^{2})
b = ( 8 * 2849 - 154 * 136 ) / ( 8 * 3204 - ( 154 )^{2})
b = 0.965
a =( Σ Y - ( b * Σ X) ) / n
a =( 136 - ( 0.9645 * 154 ) ) / 8
a = -1.567
Equation of regression line becomes Ŷ = -1.567 + 0.965 X

When X = 16
Ŷ = -1.567 + 0.965 X
Ŷ = -1.567 + ( 0.965 * 16 )
Ŷ = 14