CA Foundation P3 · Chapter 17 · Question 8 of 9
Given x̄ = 20, ȳ = 45 and the regression coefficient of y on x, byx = 1.2, the estimated value of y when x = 25 is:
Test yourself: pick an answer
Reveal answer & explanation
Correct answer: D) 51
Explanation
The regression line of y on x is y − ȳ = byx(x − x̄). So y = 45 + 1.2(25 − 20) = 45 + 6 = 51. Computing 1.2 x 25 alone gives 30, and subtracting the adjustment gives 39.
More Correlation and Regression MCQs
- Q1The coefficient of correlation r always lies between:
- Q2If Cov(x, y) = 18, σx = 4 and σy = 6, the coefficient of correlation is:
- Q3The two regression coefficients are byx = 0.8 and bxy = 0.45. The coefficient of correlation is:
- Q4For 6 pairs of ranks, the sum of squares of rank differences Σd² = 14. Spearman's rank correlation coefficient is (to two decimals):
- Q5The two regression lines are 3x + 2y = 26 and 6x + y = 31. The means of x and y are: