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CMA Foundation · Fundamentals of Business Mathematics and Statistics · Index Numbers and Time Series

A firm's sales trend is Y = 50 + 4X with origin 2019 (X in years). If the origin is shifted to 2021 with the same unit of X, what is the new equation?

The new equation is Y = 58 + 4X. Shifting the origin from 2019 to 2021 makes the intercept the trend value at X = 2, which is 50 + 8 = 58, while the slope stays 4 because the unit is unchanged.

  1. AY = 58 + 4XCorrect
  2. BY = 50 + 4X
  3. CY = 42 + 4X
  4. DY = 58 + 8X

Explanation

At the new origin 2021, the old X is 2, so the trend value is 50 + 4×2 = 58. The slope stays 4 because the unit is unchanged. Option 42 subtracts instead of adds, a sign error.

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