What variables can affect the sprouting of a bean seed?

  What variables can affect the number of books sold by a door-to-door salesperson?

  What variables can affect the number of fish in a lake?

  What variables can affect attendance at a football game?

  What variables can affect the taste of a soft drink?   What variables can affect the speed of a runner in a

100-meter dash?

  MANIPULATED (INDEPENDENT) VARIABLE

  RESPONDING (DEPENDENT) VARIABLE

  CONTROLLED VARIABLES

  A factor or condition that is intentionally changed by an investigator in an experiment

  A factor or condition that might be affected as a result of that change

  A variable that is not changed in an experiment.

Two groups of students were tested to compare their speed working math problems. Each group was given the same problems. One group used calculators and the other group computed without calculators.

Manipulated variable – use of calculators Responding variable – speed working the math

problems Controlled – same problems

Students of different ages were given the same puzzle to assemble. The puzzle assembly time was measured.

Manipulated variable – age of student Responding variable – puzzle assembly time Controlled – same puzzle

A study was done to find if different tire treads affect the braking distance of a car.

Manipulated variable – tire tread Responding variable – braking distance Controlled – same car

An experiment was performed to determine how the amount of coffee grounds could affect the taste of coffee. The same kind of coffee, the same percolator, the same amount and type of water, the same perking time, and the same electrical source were used.

Manipulated variable – amount of coffee grounds Responding variable – taste of coffee Controlled – same…

A study was attempted to find if the length of the string in a string telephone affected the sound clarity.

Manipulated variable – length of the string Responding variable – sound clarity Controlled – same string, same cups, same

tautness in string, same people measuring clarity