Chia seeds and weight loss. Chia Pets – those terra-cotta figurines that sprout fuzzy green hair – made the chia plant a household name. But chia has gained an entirely new reputation as a diet supplement. In one 2009 study, a team of researchers recruited 38 men and divided them randomly into two groups: treatment or control. They also recruited 38 women, and they randomly placed half of these participants into the treatment group and the other half into the control group. One group was given 25 grams of chia seeds twice a day, and the other was given a placebo. The subjects volunteered to be a part of the study. After 12 weeks, the scientists found no significant difference between the groups in appetite or weight loss.33
(a) What type of study is this?
(b) What are the experimental and control treatments in this study?
(c) Has blocking been used in this study? If so, what is the blocking variable?
(d) Has blinding been used in this study?
(e) Comment on whether or not we can make a causal statement, and indicate whether or not we can generalize the conclusion to the population at large.