Unit 3 - Topic 2 - Experimentation - Section B - Experimental Design - Part I - Independent and dependent variables

Question 1

What is an independent variable

Answer 1

The variable that is changed in a scientific experiment.

Question 2

What is a dependent variable

Answer 2

The variable being measured in a scientific experiment

Question 3

What can independent and dependent variables be

Answer 3

Continuous or discrete

Question 4

What do experiments involve

Answer 4

The manipulation of the independent variable by the investigator

Question 5

What 2 groups are compared

Answer 5

The experimental treatment group is compared to a control group

Question 6

Describe the use and limitations of a simple (one independent variable) experimental design

Answer 6

The control of laboratory conditions allows simple experiments to be conducted more easily than in the field. However, a drawback of a simple experiment is that its findings may not be applicable to a wider setting

Question 7

What does a multifactorial (more than one independent variable) experimental design involve

Answer 7

A multifactorial experiment involves a combination of more than one independent variable or combination of treatments

Question 8

How can there be no truly independent variable

Answer 8

Investigators may use groups that already exist

Question 9

Describe the advantages and disadvantages of observational studies

Answer 9

Observational studies are good at detecting correlation, but since they do not directly test a hypothesis, they are less useful for determining causation

Question 10

In observational studies what is not directly controlled and why

Answer 10

In observational studies the independent variable is not directly controlled by the investigator, for ethical or logistical reasons