33.6 Exercises

Selected answers are available in Sect. D.30.

Exercise 33.1 A study evaluated various food mixtures for sheep (Moir 1961). Describe the scatterplot (Fig. 33.6) in terms of the form of the relationship, the direction of the relationship (if relevant), and the variation in the relationship.

FIGURE 33.6: Scatterplots for the sheep-food data

Exercise 33.2 A study examined the direct current generated by a windmill and its association with wind speed (Hand et al. 1996; Joglekar, Scheunemyer, and LaRiccia 1989). Describe the relationship (Fig. 33.7).

FIGURE 33.7: The relationship between DC output and wind speed

Exercise 33.3 A study examined the mandible length and gestational age for 167 foetuses from the 12th week of gestation onward (Royston and Altman 1994). How would you describe the relationship (Fig. 33.8)?

FIGURE 33.8: The relationship between gestational age and mandible length

Exercise 33.4 A study examined the time taken to deliver soft drinks to vending machines (Montgomery and Peck 1992). How would you describe the relationship (Fig. 33.9)?

FIGURE 33.9: The time taken to deliver soft drinks to vending machines