Experimental Design

What kind of experiment is shown in the picture?

• Randomized Block Design

• Completely Randomized Design

• Matched Pairs

• SRS

What kind of experiment is shown?

• Matched Pairs

• Block Design

• Completely Randomized Design

• SRS

A market research company wishes to find out whether the population of students at a university prefers Starbucks or Dunkin Donuts. A random sample of students is selected, and each student is asked first to try both but the order they try them is randomly decided with a coin toss (heads: Starbucks, then Dunkin. tails: vice versa). They then indicate which brand they prefer. This is an example of

• completely randomized experiment

• observational study

• stratified sample

• matched pairs experiment

True or False: An example of a matched pair experimental design is having one twin receive treatment A and the second twin receive treatment B

• True

• False

An ​ (a)   does not have treatments imposed.

An ​ (b)   has treatments imposed.

• Observational Study

• Experiment

Match the following

• Completely Randomized Design

• Subjects do not know which treatment they are receiving, but members of the research team do, or vice versa.

• Single-Blind Study

• Neither the subjects nor the members of the research team who interact with them know which

  treatment a subject is receiving.

• Randomized Complete Block Design

• Treatments are assigned to experimental units

  completely at random.

• Matched Pairs Design

• A special case of a randomized block design. Using a blocking variable, subjects (whether they are people or not) are arranged in pairs matched on relevant factors.

• Double-Blind Study

• Treatments are assigned completely at random within each block.

In order to perform an experiment using 60 members of a gym, I first divide the list of members into men and women because I feel that the results will be different based on gender. I then randomly choose 30 men and 30 women. I assign half of the men to the treatment group and half to the control group. I repeat this procedure with the women. This is an example of a:

• randomized comparative design

• blocking design

• matched pairs design

• double blind simple random sample

An experiment will be conducted to determine whether children learn their multiplication facts better by practicing with flash cards or by practicing on a computer. Children who volunteer for the experiment will be randomly assigned to one of the two treatments. Because the children’s gender may affect the outcome, there will be blocking by gender. After practice, the children will be given a test on their multiplication facts. Why will it be impossible to conduct a double-blind experiment?

• The experimenter will know whether the child is a boy or a girl and whether he or she used flash cards or the computer.

• The child will know whether he or she is a boy or a girl.

• The child will know whether he or she used flash cards or the computer.

• The person who grades the tests will know whether the child was a boy or a girl.

• The person who grades the tests will know whether the child used flash cards or the computer.

A researcher randomly selected 30 people to participate in a study to investigate which of two materials, A or B, used in the heels of sneakers will last longer. The researcher is considering two design types for the study. Design 1: Randomly assign 15 participants to wear sneakers with material A on their left feet and material B on their right feet. The remaining participants will wear sneakers with material B on their left feet and material A on their right feet. Design 2: Randomly assign 15 participants to wear sneakers with material A on both feet and the remaining participants to wear sneakers with material B on both feet. Which of the following best describes each design?

• Design 1 is a completely randomized design, and design 2 is a matched pairs design.

• Design 1 is a matched pairs design, and design 2 is a completely randomized design.

• Design 1 is a matched pairs design, and design 2 is a matched pairs design.

• Design 1 is a completely randomized design, and design 2 is a completely randomized design.

• Design 1 is a completely randomized design, and design 2 is a randomized block with materials as blocks.

Can pleasant aromas help a student learn better? Two researchers believed that the presence of a floral scent could improve a person's learning ability in certain situations. They had 22 people work through a pencil-and-paper maze 6 times. Three of the times they wore a floral-scented mask and three times they wore an unscented mask. The three trials for each mask followed one another. Testers measures the length of time it took subjects to complete each of the six trials. They reported that, on average, subjects wearing the floral-scented mask completed the maze more quickly that those wearing the unscented mask, although, the difference was not statistically significant. This study is:

• convenience sample

• oberservational study

• experiment, but not double-blind

• double-blind experiment