Chapter 8 - Experimental Design Choices

Question 1

The key is making a design as ___________ as possible for both the active (test) group or treatment and control group.

Answer 1

identical

Question 2

What does a control allow for?

Answer 2

To test the effect of an independent variable in a comparison to doing nothing versus comparing the effects of different levels of an independent variable.

Question 3

Do you need a control group or treatment in your experimental design?

Answer 3

Depends on your question.

Question 4

What can a correlational design benefit from?

Answer 4

From a control and most manipulative studies benefit from a control.

Question 5

What are two characteristics of negative controls?

Answer 5

• Control ground could have an identical “environment” to the treatment group, but does not receive treatment.
• Control group may receive a “placebo” (important to ensure it is identical to thermal drug)

Question 6

What are two characteristics of positive controls?

Answer 6

• Two Treatments (Standard Drug and Trail Drug)
• Three treatments (standard drug, trail drug, and placebo)

Question 7

What is a Historical control?

Answer 7

Use past studies on standard drug as the control rather than having your own (important to ensure past studies are directly comparable)

Question 8

What is a Blind Control?

Answer 8

Assessor is “blind” to the assignment of individuals to treatment versus control groups.

Question 9

When can a “double blind” procedure be implemented?

Answer 9

When bot the evaluator and the research subjects are “blind” to their assignments.

Question 10

What are some pros of Controls?

Answer 10

Helps us eliminate or minimize confounding factors.

Question 11

What are the Cons of Controls?

Answer 11

Might inadvertently introduce a new confounding factor

Question 12

What is a One-factor Design?

Answer 12

One independent variable that you manipulate or measure the influence of ( or on) the dependent variable.

Question 13

How do you do a One-factor Design?

Answer 13

Assign individuals to different treatments at random from your population such that they are independent.

Question 14

In a One-factor Design, you should aim for a __________ design.

Answer 14

Balanced

Question 15

What does it mean to have a balanced design?

Answer 15

Equal number of individuals per treatment

Question 16

What is a challenge with One-factor Designs?

Answer 16

Detecting the influence of the independent variable might be tough if there is a lot of random, variation among individuals in the population.

Question 17

What is a Two-factor Design?

Answer 17

Two independent variables that you manipulate or measure the influence of (or on) the dependent variable.

Question 18

Two-factor Designs allow you to detect _____________ between independent variables.

Answer 18

interactions

Question 19

What is a blocking design?

Answer 19

You decide on a one-way design, but you have reason to suspect that not all samples in your population are totally comparable.

Question 20

Why is Blocking used?

Answer 20

As a way of ensuring each treatment group ends up containing the same number of not-quite-the-same individuals.

Question 21

What is a Crossover Design?

Answer 21

Give the same subjects different conditions over time.

Question 22

What is a Split-plot design?

Answer 22

You have two factors with three treatment levels each.

Question 23

For logistical reasons, the three treatments used in Split-plot design for a factor needs to be applied to ______ areas.

Answer 23

specific

Question 24

When using a Split-plot Design, you need to ensure each of the treatments gets the same number and type of ____________, and that the assignment of treatment is ______________.

Answer 24

Treatment, random