ITPEC FE Morning April 2021 Question 4
ITPEC FE Morning April 2021 — Question 4 of 80
Regression Line Interpretation — derive conclusions from regression parameters.
Given: x = previous year score, y = current year score.
- Correlation coefficient: 0.8
- Regression line: y = 1.1x + 10
Why (a):
- Slope 1.1 > 1 means y grows faster than x
- Intercept +10 shifts y further up
- Both factors confirm: current year scores tend to be higher
Why not others:
- (b) — correlation 0.8 measures linear association strength, not exam quality
- (c) — slope 1.1 does not mean average(y) = 1.1 × average(x); the +10 intercept breaks that ratio
- (d) — reversed: if x = 0 then y = 10, not the other way around
Key rule: In y = ax + b, the slope tells how y changes per unit of x; the intercept is y when x = 0. Don't confuse direction of axes.
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