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1.3 Exercises Experimental Design

Last updated about 1 year ago
17 questions
3

What are the 3 most important things in an experiment? (3 words)

1

Why is replication important?

4

Determine whether the statement is true or false.

  • A confounding variable occurs when an experimenter cannot tell the difference between the effects of different factors on the variable.
  • Controlling for influential/extraneous factors is not important
  • A double-blind experiment is used to increase the placebo effect.
  • A placebo is an actual treatment
  • True
  • False
2

To attract more customers, a coffee shop owner experiments by remodeling the shop using bright colors. At the same time, a shopping mall nearby has its grand opening. Business at the coffee shop increases. Does this mean that the bright colors attracted more customers? Explain.

4
  • To study predator-prey relationships in the Bering Sea, researchers looked at the feeding behaviors of three species: Black-legged kittiwakes, thick-billed murres, and northern fur seals.
  • In a survey of 177,237 U.S. Adults, 65% said they visited a dentist in the last 12 months.
  • Researchers demonstrated in people at risk for increased cardiovascular disease that 200 milligrams per day of acetyl-L-carnitine over a 24-week period lowered blood pressure and improved insulin resistance.
  • To study the effect of music on driving habits, eight drivers (four male and four female) drove 500 miles while listening to different genres of music.
  • Observational Study
  • Experiment
A pharmaceutical company wants to test the effectiveness of a new allergy drug. The company identifies 250 females ages 30 to 35 who suffer from severe allergies. The subjects are randomly assigned into two groups. One group is given the drug and the other is given a placebo that looks exactly like the drug. After six months, the subjects' symptoms are studied and compared.
1

a) Identify the Experimental Units (Subjects) used in this experiment

1

b) Identify the treatment in this experiment

1

c) Identify a potential problem with the experimental design being used and suggest a way to improve it

1

d) How could this experiment be designed to be double-blind

A footwear company developed a new type of shoe designed to help delay the onset of arthritis in the knee. Eighty people with early signs of arthritis volunteered for a study. One-half of the volunteers wore the experimental shoes and the other half wore regular shoes that looked exactly like the experimental shoes. The individuals wore the shoes every day. At the conclusion of the study, their symptoms were evaluated and MRI tests were performed on their knees.
1

a) Identify the Experimental Units used in this experiment.

1

b) Identify the Treatments used in this experiment.

1

c) Identify a Potential Problem with the experimental design being used and suggest a way to improve it.

1

d) Describe how this experiment is placebo-controlled

1

e) Describe how this experiment is a double-blind study

1

f) Of the 80 volunteers, 40 are men and 40 are women, How could blocking be used in designing this experiment?

1

Write down the calculator command needed to generate fifteen numbers between 1 and 150.

1

An experimenter is testing the effects of a new weight loss drink. Determine which experimental design is described.

  • The experimenter divides the subjects into age categories such as 30-39 years old, 40-49 years old, and over 50 years old. Within each age group, subjects are randomly assigned to either the treatment or the control group.
  • The experimenter randomly assigns 50 subjects to either treatment group or control group.
  • The experimenter pairs up each subject according to similar weight. One subject is randomly chosen to get the treatment and the other the placebo.
  • Completely Randomized Design
  • Randomized Block Design
  • Matched Pairs Design