The equation of a line of best fit (AQA GCSE Statistics): Flashcards
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What is the equation of a line of best fit?
What is the equation of a line of best fit?
y = ax + b, where a is the gradient and b is y-intercept.
How do you calculate the gradient (a)?
How do you calculate the gradient (a)?
Gradient = height ÷ base using two points on the line.
Find the gradient between (2, 3) and (5, 9).
Find the gradient between (2, 3) and (5, 9).
Gradient = (9-3) ÷ (5-2) = 6 ÷ 3 = 2.
What does a positive gradient indicate?
What does a positive gradient indicate?
A positive gradient indicates a positive correlation.
How to find the y-intercept (b)?
How to find the y-intercept (b)?
Use b = y - ax with a point on the line.
Calculate b using point (4, 10) and a=1.5.
Calculate b using point (4, 10) and a=1.5.
b = 10 - (1.5 * 4) = 10 - 6 = 4.
What does a gradient of 3 mean in context?
What does a gradient of 3 mean in context?
For each unit increase in x, y increases by 3.
Why is using the scale on axes important?
Why is using the scale on axes important?
It ensures accurate gradient calculations, avoiding errors.
What is the equation if a=2 and b=5?
What is the equation if a=2 and b=5?
y = 2x + 5.
What does a negative gradient indicate?
What does a negative gradient indicate?
A negative gradient indicates a negative correlation.