4.18 Optional: Percentages
This question is optional; for example, if you need more practice, or you are studying for the exam.
(Answers are available in Sect. A.5)
Industries often produce unpleasant odours, but the effects on the health of those impacted is not always clear.
Furthermore, different communities are impacted in different ways. One study (Deane and Sanders 1978) researched the RQ:
In Carson, California, does the odour from nearby petroleum refineries impact residents in different areas differently?
One aim of the study was to determine if the reports of unpleasant odours were related to measurements made by a dynamic olfactometer (an 'electronic nose'). Part of the data collected are shown in Table 4.5.
|Area I||Area II||Area III||Total|
|At least once a week||48||48||16||112|
|Between once a week and once a month||23||21||10||54|
|Less often than once a month||14||14||20||48|
|Not at all||12||12||53||77|
- Explain whether the study is observational or experimental (true or quasi).
- What would be the meaning of column percentages for this table?
- What would be the meaning of row percentages for this table?
- Would row or column percentages probably be more sensible to use? Why?
- Compute the percentage of residents in the sample overall not detecting the odour at all.