Experimental Design Statistics

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

• an oberservational study

• an experiment, but not double-blind

• a double-blind experiment

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

They are attempts to establish a cause-and-effect relationship between two variables by manipulating one variable.

• Observations

• Experiments

• Correlations

• Self-reports

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

What type of study is described? A gym tries out a new weightlifting method to see if it will build muscle for their customers faster than their current method.

• Sample Survey

• Experiment

• Observational Study

Which of the following is a key distinction between well designed experiments and observational studies?

• More subjects are available for experiments than for observational studies.

• Ethical constraints prevent large-scale observational studies.

• Experiments are less costly to conduct than observational studies.

• An experiment can show a direct cause-and-effect relationship, whereas an observational study cannot.

• Tests of significance cannot be used on data collected from an observational study.

Does listening to classical music while studying increase test scores?

• Survey

• Observational study

• Experimental study

Identify the design  for the experiment

• completely randomized, the treatment is pesticide

• randomized block, blocked on tree type, the treatment is pesticide

• This experiment is single blind, blocked by pesticide

• The experiment is double blind, the factors are tree type and pesticide

Elise gave each member of the class a random cookie, some from recipe A and some from recipe B. Then she observed which students returned for a second cookie. What are the treatments in this scenario?

• The Students

• Students who returned for a cookie

• The different cookie types/recipes

• Whether the student returned for a second cookie

Disneyland often surveys its guests as they exit a restaurant during their visit. The surveyor stands at the restaurant exit, counts the number of people leaving, and surveys every 25th guest.
This is a form of:

• Simple Random Sample

• Stratified Random Sample

• Voluntary Response

• Systematic Random Sampling