Statistics Experimental Design

Dentists want to know if a fluoride mouth wash will help prevent cavities. After 6 months, they will compare the number of cavities in those who used the mouth wash versus those who did not. Which is an example of a matched pairs design for this experiment?

• Dentists sort 40 patients into groups based on age, such as 10-14, 15-20, 21-26, and 26-30. Half of the patients in each group are given the mouth wash, half are not.

• Dentists sort 50 patients into pairs that are the same age. 1 person is given the mouth wash and 1 is not.

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

• an observational study

• a blocked experiment

• matched pairs experiment

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:

• completely randomized experiment

• blocked experiment

• matched pairs experiment

• observational study

Participants are assigned to groups, based on gender. Then, within each group, participants are randomly assigned to treatments. For this design, 250 men get the placebo, 250 men get the vaccine, 250 women get the placebo, and 250 women get the vaccine. What type of experiment design is this?

• Completely Randomized Experiment

• Matched Pairs Experiment

• Blocked Experiment

An ​ (a)   does not have treatments imposed.

An ​ (b)   has treatments imposed.

• Observational Study

• Experiment

Match the following

• 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

• 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.

• Completely Randomized Design

• Treatments are assigned completely at random within each block.

Researchers want to know how diet influences a child's brain development. In a sample of 100 5 year old children, 20 of the children are given a vegan diet, 20 are given a pescatarian diet, 20 are given a standard American diet, and 20 are given a paleo diet. This is an example of...

• a matched pair, with pairs determined by diet type

• a block design, with blocks determined by age.

• a block design, with blocks determined by diet type.

• a completely randomized experiment

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 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.