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

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

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

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

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

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

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

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

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

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

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

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

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