general layout for experimental design diagram
GENERAL LAYOUT FOR EXPERIMENTAL DESIGN DIAGRAM TITLE The effect of _________________________________________ (independent “Manipulated” variable) On __________________________________________________(dependent “Responding” variables) HYPOTHESIS If ____________________________________(planned change in independent “Manipulated” variable) Then__________________________________(predicted change in dependent “Responding” variables) INDEPENDENT “Manipulated” VARIABLE __________________________________________________________________ LEVELS OF INDEPENDENT “Manipulated” VARIABLE & NUMBERS OF REPEATED TRIALS Level 1 (control)
Level 2
Level 3
Level 4
Number of trials
Number of trials
Number of trials
Number of trials
DEPENDENT “Responding” VARIABLES AND HOW WERE THEY MEASURED __________________________________________________________ __________________________________________________________ CONSTANTS “Controlled Variables” 1. 2. 3. 4. 5. PROCEDURE DATA ORGAINZATION GRAPHIC REPRESENTATION
Eleven parts of the Experimental Design Diagram 1.
Title for experiment written as “the effect of the independent variable on the dependent variable”
2.
Hypothesis in the form of an “if-then” statement
3.
Independent variable
4.
Different levels of the independent variable
5.
Level of the independent variable that will serve as the control for the experiment
6.
Number of repeated trials for each level of the independent variable
7.
Dependent variables, including how they will be measured
8.
Constants
9.
Procedure: statements on how to carry out the experiement
10.
Data organization…is it a table,
11.
Graphic representation…can the data be graphed and what is the outcome of the graph?
Example of an Experimental Design Diagram TITLE
The Effect of Type of Insulation Wrap on Temperature of Water in a Jar
HYPOTHESIS
If jars of water in the sun are wrapped with different types of insulation, then the temperature of the water in the jars will increase by different amounts.
INDEPENDENT VARIABLE
Type of insulation
LEVELS OF INDEPENDENT VARIABLE AND NUMBERS OF REPEATED TRIALS No insulation (Control)
Cotton
Wool
Nylon
3 jars
3 jars
3 jars
3 jars
DEPENDENT VARIABLE AND HOW MEASURED
Change in temperature of water in jar, measured in degrees Celsius
CONSTANTS 1. 2. 3. 4.
All jars are identical All jars are fitted with the same plastic lids All jars half-filled with water All jars placed in direct sunlight
PROCDURE; Using identical jar, place insulation of cotton, wool and nylon around 3 jars each. An additional 3 jars are used with no insulation as a control Fill each jar one-half full of water and place an identical plastic lid on each. Place all 12 jars in direct sunlight. Leave in sun for 4 hours, then measure the temperature of each jar. Place data in table. Average temperature for each insulation type. Place results in data table. Graph average data on graph. DATA TABLE No insulation Cotton Wool Nylon Temperature (oC)
Average Temperature GRAPHIC REPRESENTATION
Water Temperature (oC)
Water Temperature vs. Insulation Type
No Insulation
Cotton
Wool
Type of Insulation
Nylon
EXPERIMENTAL DESIGN
We are concerned with the analysis of data generated from an experiment. It is wise to take time and effort to organize the experiment properly to ensure that the right type of data, and enough of it, is available to answer the questions of interest as clearly and efficiently as possible. This process is called experimental design. The specific questions that the experiment is intended to answer must be clearly identified before carrying out the experiment. We should also attempt to identify known or expected sources of variability in the experimental units since one of the main aims of a designed experiment is to reduce the effect of these sources of variability on the answers to questions of interest. That is, we design the experiment in order to improve the precision of our answers. Items to discuss Proper question to investigate. Variables o Dependent o Independent Form a hypothesis. What materials are needed? What is the control in the experiment? What constants are needed? How will you organize the data? Visual representation of data ( graphs, charts, etc)
Level 2
Level 3
Level 4
Number of trials
Number of trials
Number of trials
Number of trials
DEPENDENT “Responding” VARIABLES AND HOW WERE THEY MEASURED __________________________________________________________ __________________________________________________________ CONSTANTS “Controlled Variables” 1. 2. 3. 4. 5. PROCEDURE DATA ORGAINZATION GRAPHIC REPRESENTATION
Eleven parts of the Experimental Design Diagram 1.
Title for experiment written as “the effect of the independent variable on the dependent variable”
2.
Hypothesis in the form of an “if-then” statement
3.
Independent variable
4.
Different levels of the independent variable
5.
Level of the independent variable that will serve as the control for the experiment
6.
Number of repeated trials for each level of the independent variable
7.
Dependent variables, including how they will be measured
8.
Constants
9.
Procedure: statements on how to carry out the experiement
10.
Data organization…is it a table,
11.
Graphic representation…can the data be graphed and what is the outcome of the graph?
Example of an Experimental Design Diagram TITLE
The Effect of Type of Insulation Wrap on Temperature of Water in a Jar
HYPOTHESIS
If jars of water in the sun are wrapped with different types of insulation, then the temperature of the water in the jars will increase by different amounts.
INDEPENDENT VARIABLE
Type of insulation
LEVELS OF INDEPENDENT VARIABLE AND NUMBERS OF REPEATED TRIALS No insulation (Control)
Cotton
Wool
Nylon
3 jars
3 jars
3 jars
3 jars
DEPENDENT VARIABLE AND HOW MEASURED
Change in temperature of water in jar, measured in degrees Celsius
CONSTANTS 1. 2. 3. 4.
All jars are identical All jars are fitted with the same plastic lids All jars half-filled with water All jars placed in direct sunlight
PROCDURE; Using identical jar, place insulation of cotton, wool and nylon around 3 jars each. An additional 3 jars are used with no insulation as a control Fill each jar one-half full of water and place an identical plastic lid on each. Place all 12 jars in direct sunlight. Leave in sun for 4 hours, then measure the temperature of each jar. Place data in table. Average temperature for each insulation type. Place results in data table. Graph average data on graph. DATA TABLE No insulation Cotton Wool Nylon Temperature (oC)
Average Temperature GRAPHIC REPRESENTATION
Water Temperature (oC)
Water Temperature vs. Insulation Type
No Insulation
Cotton
Wool
Type of Insulation
Nylon
EXPERIMENTAL DESIGN
We are concerned with the analysis of data generated from an experiment. It is wise to take time and effort to organize the experiment properly to ensure that the right type of data, and enough of it, is available to answer the questions of interest as clearly and efficiently as possible. This process is called experimental design. The specific questions that the experiment is intended to answer must be clearly identified before carrying out the experiment. We should also attempt to identify known or expected sources of variability in the experimental units since one of the main aims of a designed experiment is to reduce the effect of these sources of variability on the answers to questions of interest. That is, we design the experiment in order to improve the precision of our answers. Items to discuss Proper question to investigate. Variables o Dependent o Independent Form a hypothesis. What materials are needed? What is the control in the experiment? What constants are needed? How will you organize the data? Visual representation of data ( graphs, charts, etc)
