Errors in solution for Question 25 in Chapter 5

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Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
62/100
Issue type
Documentation
Clarity
Clearly specified
Activity status
Stale
Tech stack
r
Domain
content, documentation

Research direction

Open the linked Chapter 5 exercise-solutions page and review the histogram, map, and Question 25 solution text. Verify the claims about counties above 90% Hispanic and the map's shading direction, then correct the inaccurate wording so the written solution matches the displayed figures.

Written by the indexing model from the issue text.

Description

The solution provided for question 25 in chapter 5 contains answers that are hard to discern from the provided histogram and also appears to contain an error in part (b).

(a) The distribution of percentage of population that is Hispanic is extremely right skewed with majority of counties with less than 10% Hispanic residents. However there are a few counties that have more than 90% Hispanic population. It might be preferable to, in certain analyses, to use the log-transformed values since this distribution is much less skewed. (b) The map reveals that counties with higher proportions of Hispanic residents are clustered along the Southwest border, all of New Mexico, a large swath of Southwest Texas, the bottom two-thirds of California, and in Southern Florida. In the map all counties with more than 40% of Hispanic residents are indicated by the darker shading, so it is impossible to discern how high Hispanic percentages go. The histogram reveals that there are counties with over 90% Hispanic residents. The histogram is also useful for estimating measures of center and spread. (Emphasis added.)

It is very hard to discern from the histogram of % Hispanic that any counties are higher than 90% Hispanic. The histogram makes it look like the highest observed values are somewhere around 80, no bars are visible above 90%. Accessing the data and running R or Stata, one can see that 8 counties had > 90% Hispanic population in 2010, but that's the only way I could see that.

The part of the solution on part (b) that says, "all counties with more than 40% of Hispanic residents are indicated by darker shading" does not match the presented map. I'm wondering if the reference to "40%" was accidentally based on the map for question 24. But either way, the map uses lighter shading for counties with higher % Hispanic, not darker.

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