1.)ANew York Timesarticle reported a study that investigated whether giving flu shots to schoolchildren protects a whole community from the disease. Researchers in Canada recruited 49 remote Hutterite farming colonies in western Canada for the study. In 25 of the colonies, all children aged 3 to 15 received flu shots in late 2008; in the 24 other colonies, they received a placebo. Which colonies received flu shots and which received the placebo was determined by randomization, and the colonies did not know whether they received the flu shots or the placebo. The researchers recorded the percentage of all children and adults in each colony who had laboratory-confirmed flu over the ensuing winter and spring.

2.)Use theTable of Random Digitsto randomly assign the 4 subjects in each block (created by arranging the subjects in order by weight) to the 4 weight-loss treatments. Number from 1 to 4 within each block and then, starting at line 133, assign each member of block 1 to a weight-loss treatment.

Outline the design of this experiment.

3.)A researcher was interested in whether the order of the answers to multiple-choice questions affects exam scores. He made three versions of an exam. Each version had the same questions and the same set of answers, but the order of the possible answers was different for each version. The three versions were given to students in each of two classes having different instructors. Each class had an enrollment of 75 students. The researcher was concerned that scores might also depend on instructor, so instructor (class) was treated as a blocking variable.

Which diagram below outlines a correct diagram for this experiment?