Variables and hypothesis

• What is a dependant variable?


  What you are measuring
• What is an independent variable?


  What you change
• What is a control variable?


  What you keep the same
• What is an extraneous variable?

  Any other variable that could affect the IV
• What is a confounding variable?


  An extraneous variable that causes a change to the DV
• What is operationalising?

  Making a variable measurable
• What is a hypothesis?

  A prediction
• What is a directional (one-tailed) hypothesis?


  Tells us how the IV will affect the DV
• What is a non-directional (two-tailed) hypothesis?


  Tells us the IV will affect the DV, but not how it will do this
• What is a null hypothesis?

  A null hypothesis is a statement that assumes there is no significant relationship or difference between variables
• What is an example of a directional hypothesis?

  Caffeine will increase alertness
• What is an example of a non-directional hypothesis?

  Caffeine will affect alertness
• What is an example of a null hypothesis?

  There will be no change in alertness (DV) due to caffeine consumption. Any change in alertness is due to chance