Experimental Design

Question 1

What is anecdotal evidence?

Answer 1

Information based on personal experience and observation

Question 2

What is random assignment?

Answer 2

An experiment were all observational units in a population have equal chance of being assigned to either of the groups and all groups are as similar as possible

Question 3

What is a randomized comparative experiment?

Answer 3

An experiment in which there are multiple groups being compared and random assignment is used to make the groups as similar as possible

Question 4

What does statistically significant mean?

Answer 4

When the comparison groups are similar and the difference between the two groups is large enough that it cannot be explained by the slight differences between them and it can therefore be concluded that the difference is a result of the treatment imposed on the groups

Question 5

What are the elements of a general experimental design diagram?

Answer 5

Observational units/trials –> treatment one vs. treatment two –> comparison of the two groups (e.g., mean or proportion)

Question 6

What are the four principles of experimental design?

Answer 6

Comparison, random assignment, control, and replication

Question 7

What is comparison?

Answer 7

An experimental design that compares two or more treatments

Question 8

What is random assignment?

Answer 8

An experimental design where experimental/observational units have equal chance of being assigned to the treatment groups in an attempt to make the treatment groups are similar as possible

Question 9

What is control?

Answer 9

An experimental design where all variables aside from the explanatory variable are kept the same between the treatment groups

Question 10

What is replication?

Answer 10

Enough experimental/observational units are used that differences between the groups can be assumed to be caused by the explanatory variable rather than chance

Question 11

What is the goal of random assignment?

Answer 11

To eliminate confounding variables and allow a cause-and-effect conclusion to be drawn by comparing two or more treatment groups

Question 12

What is blindness?

Answer 12

Either the observational/experimental units or researchers or both (double-blindness) are unaware of which observational/experimental units are in each treatment group, preventing bias in the treatment of the groups or effects like the Placebo effect from occurring

Question 13

What is the disadvantage of anecdotal data?

Answer 13

Experimental design is likely to be biased and have confounding variables, preventing a cause-and-effect conclusion from confidently being drawn