Think About It

  1. 23. No. Square the correlation. These share ¼ of their variation.

  2. 25. No. Least squares minimizes vertical deviations. If reversed, the deviations are horizontal in the plot of y on x.

  3. 27. se = $32. If bell−shaped, then ±2 se holds about 95% of the residuals.

  4. 29. The slope becomes steeper, producing a higher cost per mile driven. The intercept would increase as well.

  5. 31. They are the same.

  6. 33.

    1. Yes. The equation has a constant plus 85 times the number of shoppers.

    2. The intercept is about 0 but is likely to be a large extrapolation.

    3. The slope is about 85$/shopper.

    4. The variation may increase.

  7. 35.

    1. The intercept of $47,000 is likely an extrapolation and not directly interpretable. The slope is $650 per square foot. For every one−square−foot ...

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