1. Independent variable (X) – variable that can be controlled or manipulated.
Dependant variable (Y) – variable that cannot be controlled or manipulated

2. Independent variables are…
What is being tested
What is being changed
The difference between the groups
The ‘cause’ of a change

3. Dependent variables are…
What is observed
What is measured
The data
The ‘effect’ caused by the independent variable

4. How to remember…??? D – dependant variable
R – responding (answers change, effect)
Y – y axis
M – manipulated (change, cause)
I – independent variable
X – x axis

5. For example… Number of minutes a candle burns and the candle’s height
The height of the candle DO the number of minutes burned.
The more minutes the lower the height.
The height of the candle effect time cause
IND = time (minutes)
DEP = height of the candle
D – dependant variable
R – responding (answers change, effect)
Y – y axis
M – manipulated (change, cause)
I – independent variable
X – x axis

6. Outside temperature and A/C cost
A/C cost DO the outside temperature
The higher the temperature the higher the A/C cost.
Temperature outside – cause A/C cost - effect
IND = temperature outside
DEP = A/C cost
D – dependant variable
R – responding (answers change, effect)
Y – y axis
M – manipulated (change, cause)
I – independent variable
X – x axis

7. Number of word written and amount of ink remaining in pen
Ink remaining DO the number of words written
The more words you write the less ink you have.
Number of words written – cause Ink remaining - effect
IND = the number of words
DEP = ink remaining
D – dependant variable
R – responding (answers change, effect)
Y – y axis
M – manipulated (change, cause)
I – independent variable
X – x axis

8. A child’s age and the child’s height
Height DO the Age
The older you are the taller you are.
age – cause height - effect
IND = age
DEP = height
D – dependant variable
R – responding (answers change, effect)
Y – y axis
M – manipulated (change, cause)
I – independent variable
X – x axis

9. The selling price on a calculator and the number of functions it contains
The selling price DO the number of functions
The more functions you have the higher the selling price
Cause number of functions Effect price
IND = number of functions
DEP = selling price
D – dependant variable
R – responding (answers change, effect)
Y – y axis
M – manipulated (change, cause)
I – independent variable
X – x axis

10. Age of car and value of car
Value of the car DO the age of the car
The older the car the lower the value
Cause age Effect value
IND = age
DEP = value
D – dependant variable
R – responding (answers change, effect)
Y – y axis
M – manipulated (change, cause)
I – independent variable
X – x axis

11. A company charges $10 per hour to rent a bulldozer.
The total cost DO the number of hours
The more hours you rent the higher the total cost.
Cause = hours Effect = total cost
IND = number of hours
DEP = total cost
D – dependant variable
R – responding (answers change, effect)
Y – y axis
M – manipulated (change, cause)
I – independent variable
X – x axis

12. Size of ice cream vs. number of calories
Hot chocolate sold and temperature outside
The number of calories DO size of ice cream
IND = Cause – size of ice cream DEP = Effect – number of calories
Number of hot ch. Sold DO temperature outside
IND = Cause – temperature DEP = Effect – hot ch sold
D – dependant variable
R – responding (answers change, effect)
Y – y axis
M – manipulated (change, cause)
I – independent variable
X – x axis

13. A. Cost of shipping a package and the weight B
A. Cost of shipping a package and the weight B. Time to get home and speed you walk C. Number of calories burned and time exercising D. Amount of free time and the number of classes taken
D – dependant variable
R – responding (answers change, effect)
Y – y axis
M – manipulated (change, cause)
I – independent variable
X – x axis
A. IND = weight DEP = cost
B. IND = speed DEP = time
C. IND = exercising DEP = calories
D. IND = number of class DEP = time