Question

Read the following news article: “Wrap up” advice to stop colds Scientists say cold noses reduce ability to fight virus attacks Monday, November 14, 2005; Posted: 4:47 p.m. EST (21:47 GMT) LONDON, England (CNN) – British researchers into the common cold say “catching a chill” really does help colds develop – and are advising to “wrap up warm” to keep viruses at bay. Mothers and grandmothers have long warned that chilling the surface of the body, through wet clothes, feet and hair, causes common cold symptoms to develop. But much previous research has dismissed any link between chilling and viral infection as having no scientific basis. Now researchers in Cardiff, Wales, say they can prove drops in temperature to the body really can cause a cold to develop. Claire Johnson and Professor Ron Eccles, from Cardiff University’s Common Cold Center, recruited 180 volunteers, half of whom they got to immerse their feet in ice and cold water for 20 minutes. The other 90 in tests during the common cold “season” sat with their feet in an empty bowl. During the next four or five days, almost a third (29 percent) of the chilled volunteers developed cold symptoms – compared to just 9 percent in the control group, the scientists said.

(a) Is this an observational study or a designed experiment? Explain briefly.

(b) What is the “treatment” in this study?

(c) The article does not say how the researchers divided up the 180 people into two groups of 90. How should they do this? Explain clearly.

(d) Is the study blind? Explain briefly.

(e) Are there any possible confounding factors or problems with the study? Explain clearly.

Answer 1

(a)

This is a designed experiment and not observational study because here we have two independent basic groups: acontrol and a treatment group and specific treatment is applied to the group and effects are recorded.

(b)

Treatment in this study is immerse their feet in ice and cold water for 20 minutes.

(c)

They should divide up the 180 people into two two groups of 90 by employing Statistical Random Sampling procedure.

(d)

The study is not blind because in thisexperiment both the participants and the experimenter know who is receiving a particular treatment.

(e) Possible confounding factor with the study is the natural resistance power of each individual participant of the study.