13 Experimental Design

Question 1

What is the definition of experimental design?

Answer 1

A detailed PLAN for collecting and using data to identify causal relationships

It allows data collection efforts to detect effects and test hypotheses that answer research questions.

Question 2

Define experimental error.

Answer 2

The effect of factors other than those controlled by the researcher

Experimental error should be minimized by keeping non-investigated factors consistent.

Question 3

What is a paired comparison?

Answer 3

A method of comparing data in pairs to judge which is preferable or has a certain level of some property

This method helps reduce variability and experimental error.

Question 4

What is the purpose of randomisation in experimental design?

Answer 4

To prevent unconscious and unsuspected bias

Randomisation helps ensure that the sample selected has not been influenced by bias.

Question 5

What is a control group?

Answer 5

A set of subjects separated from the rest of the experiment, where the independent variable being tested cannot influence the results

Control groups are essential for comparison with experimental groups.

Question 6

What is an experimental group?

Answer 6

The set of subjects being tested for a reaction to change in the variable

Experimental groups are compared against control groups.

Question 7

What is a blind study?

Answer 7

A study where the control group is given a placebo, making the participants unaware of their group assignment

This helps to eliminate bias in patient responses.

Question 8

What is a double-blind study?

Answer 8

A trial where neither the administrator nor the participant knows if they are receiving the treatment or placebo

This limits experimental error from both the administrator and participant.

Question 9

What is a randomised block design?

Answer 9

A type of experiment where subjects that share certain characteristics are grouped together to form blocks, and then random allocation occurs

Analysed by two-factor ANOVA

Question 10

What is a blocking factor?

Answer 10

A factor or characteristic used to create blocks in an experiment

Blocking factors help control for variability among subjects.

Question 11

What is the significance of replication in experiments?

Answer 11

To estimate experimental error by taking repeated observations under identical conditions

Replication increases the reliability of the results.

Question 12

True or false: Exploratory data analysis involves collecting data in a specified manner.

Answer 12

FALSE

Exploratory data analysis refers to producing summary statistics from large, haphazardly collected data.

Question 13

What is the purpose of significance level in hypothesis testing?

Answer 13

To determine the threshold at which results are considered statistically significant

Common significance levels include 1%, 5%, and 10%.

Question 14

What is the role of random samples in data analysis?

Answer 14

To ensure that the sample selected has not been influenced by bias

A random sample gives all possible samples an equal chance of being selected.

Question 15

Fill in the blank: An ________ is a data collection procedure that occurs in controlled conditions to identify and understand causal relationships between variables.

Answer 15

EXPERIMENT

Experiments are designed to test hypotheses under controlled conditions.

Question 16

What is the benefit of using paired comparisons in experiments?

Answer 16

To minimize experimental error due to physiological differences

Paired comparisons help control for variability among subjects.

Question 17

What is the difference between designed experiments and exploratory data analysis?

Answer 17

Designed experiments collect data in a specified manner, while exploratory data analysis deals with haphazardly collected data

Designed experiments have a clear purpose and method of analysis.

Question 18

What are the three named experimental designed?

Answer 18

• Completely Randomised Design
• Randomised Block Design
• Repeated Measures

Question 19

What are the features of completely randomised design?

Answer 19

Each participant is randomly allocated to one group

Question 20

What is randomised block design?

Answer 20

Each participant is split into groups based on one factor and then randomly allocated to groups based on a second factor

Question 21

What is repeated measures?

Answer 21

All participants do all conditions

Question 22

How is completely randomised design data analysed?

Answer 22

One-factor ANOVA

Question 23

How is randomised block design data analysed?

Answer 23

Two-factor ANOVA