Understanding Hypothesis- your prediction

Experimental Hypothesis- there will be a difference and here is what I think it will be and why (based on previous research)

Null Hypothesis- the ‘hypothesis of no difference’. The IV won’t affect the DV

More about Variables

The experimenter manipulates the independent variable (IV) to see what affect it will have on the dependent variable (DV)

Extraneous variables are variables that could have an impact on the DV. You have to try and put in controls to eliminate extraneous variables

If an extraneous variable does impact the result it is known as a confounding variable

Observer bias happens when the researcher unconsciously influences the participants responses (tone of voice changes, etc)

Hawthorne Effect is the tendency for participants to alter their true behaviour merely because they know they’re bring observed

The case of Kluger Hans the mathematical horse, 1904

Purposive sampling intentionally selects participants based on aCriteria

When evaluating studies you should critically analyze if any bias is present

How to Limit BiasIn a single blind procedure, participants have no idea which group they’re in (eg- drug trial, either given the drug or a placebo). Eliminates the hawthorne effect.

In a double blind procedure neither the participants or the experimenter know which group subjects are in. Eliminates observer bias.

Experimental DesignsIn a Repeated Measures Designs (RMD) each participant is tested in both conditions of the experiment (drug and placebo)

In a Independent Groups Design (IGD) different participants are used in each of the conditions so each group is independent of each other (need to be randomly assigned)

In your Experiment you should identify which design you used.