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NDA 1 2024 Maths, question 103

Topic: Statistics

Q103

From data (−4,1),(−1,2),(2,7)(-4,1),(-1,2),(2,7) and (3,1)(3,1), the regression line of yy on xx is obtained as y=a+bxy=a+bx, then what is the value of 2a+15b2a+15b ?

  1. (a) 66
  2. (b) 1111Correct answer
  3. (c) 1717
  4. (d) 2121

Solution.

Answer: (b) 1111

  1. The means are x̄ = 0 and ȳ = 11/4, so a = 11/4.
  2. Also Σxy = 11 and Σx² = 30, giving b = 11/30.
  3. Thus 2a + 15b = 11/2 + 11/2 = 11.