untitled

Runners after an ultramarathon commonly develop respiratory infections. We want to know if taking 600 milligrams of vitamin C daily will reduce these infections. Researchers randomly assigned 100 ultramarathon runners to receive either vitamin C or placebo. All subjects were watched for 14 days after the big race to see if infections developed. The type of design used here?

• matched pairs
• randomized block
• completely randomized
• stratified 

Tags

CCSS.HSS.IC.B.3

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:

• a convenience sample
• an oberservational study
• an experiment, but not double-blind
• a double-blind experiment

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.B.5

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

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.B.5

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

• a completely randomized experiment
• an observational study
• a stratified sample
• a matched pairs experiment

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.B.5

Identify the design  for the experiment

• completely randomized, the factor is pesticide
• randomized block, blocked on tree type, the factor is pesticide
• This experiment is single blind, blocked by pesticide
• The experiment is double blind, the factors are tree type and pesticide

Tags

CCSS.HSS.IC.B.3

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.

Tags

VAR-3.C

The most important advantage of experiments over observational studies is that

• A) experiments are usually easier to carry out
• B)Experiments can usually give better evidence of causation
• C) Confounding cannot happen in experiments
• D) Observational studies cannot use random samples

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.B.5

What are the principles of a well-designed study?

• Random Assignment

• Control

• Replication

• Comparison

• All of the above

Tags

CCSS.HSS.IC.B.3

CCSS.HSS.IC.B.5

Which experimental method involves studying each and every member of the population of interest?

• Sampling

• Census

• Random Sampling

• Block Design

Stephen observed students entering a classroom for class and recorded whether they were in dress code.

What data collection method was used

• Observational Study

• Experimental Study

• Block Design

• Randomized

Tags

CCSS.HSS.IC.B.3