Math Problem Statement

A forester shows the accompanying histogram of tree diameters he used in analyzing 27 trees in a large woods that was for sale. Was he justified in using a Normal model to analyze the woods? Explain, citing some specific concerns.

Solution

Looking at the histogram of tree diameters, we need to assess whether the distribution is appropriate for a Normal model. A Normal model is generally suitable if the histogram is both unimodal (having a single peak) and symmetric (evenly distributed around the mean).

Answer Analysis:

The histogram in the image appears to have multiple peaks and does not exhibit strong symmetry; it has fluctuations in the number of trees across different diameter ranges without a clear, single peak and symmetry. Therefore, a Normal model might not be suitable in this case.

Here’s an evaluation of the options:

  • Option A: Incorrect, because the histogram does not appear to be both unimodal and symmetric.
  • Option B: Incorrect, as the histogram may show some degree of unimodality, but lacks symmetry.
  • Option C: Correct. The histogram is roughly unimodal but not symmetric, making a Normal model unsuitable.
  • Option D: Incorrect, as it is not clearly symmetric either.

The correct answer is: C. No, because while the histogram is unimodal, it is not symmetric.

Would you like more details on the reasoning or have any questions?

Related Questions

  1. What characteristics are necessary for a dataset to be considered approximately normal?
  2. How can the skewness of a histogram affect the choice of a statistical model?
  3. In what situations would a different model, such as a Poisson or exponential model, be more appropriate?
  4. What methods can be used to check for normality in a dataset besides visual inspection of a histogram?
  5. Why might the forester want a Normal model for analyzing tree diameters?

Tip: When assessing normality, always consider both the shape (unimodal vs. multimodal) and the symmetry (balanced vs. skewed) of the data distribution.