## 8.8 Quick review questions

Formwork is used in construction using reinforced concrete. It is complicated and labour intensive. An observational study examined the relationship between the floor area of the building (in m2 per storey) and the number of hours of labour needed for the construction (in person-minutes per storey).

The researchers also recorded, among other things:

• the average age of the workers (in years);
• the average years of experience of the workers (in years); and
• the storey height (in meters)

for each of $$n=15$$ multi-storey buildings in the study. Some data was obtained from

… interviews [..] conducted with the relevant person-in-charge of scheduling for each project.

, p. 2

To record the number of person-hours of labour:

Two observers made the site rounds observation of 2 to 40 workers. Observations were carried out continuously from the start to the end of work, excluding lunch time.

, p. 2

1. The explanatory variable is
2. The response variable is
3. What is the best description for the variable ‘Average age of the workers?’
4. What is the most likely way in which confounding would be managed in this study?
5. True or false: The carry-over effect is likely to be a big problem in this study.
6. True or false: The Hawthorne effect is likely to be a big problem in this study.
7. True or false: The placebo effect is likely to be a big problem in this study.
8. True or false: The observer effect is likely to be a big problem in this study.
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### References

Mine N, Wai SH, Lim TC, Kang W. An observational study on the productivity of formwork in building construction. ISARC Proceedings of the international symposium on automation and robotics in construction. IAARC Publications; 2015. p. 1.