Who to Test  Population: Everyone who could possibly be in the study Entire School  Random Sample: Only the people we actually test  Random: Everyone had an equal chance of being selected  All class periods were put into a hat, our class was selected at random

Random Assignment  Determines who will be assigned to the experimental and control group  Place your random sample BACK INTO THE HAT and pulling names out again.  We use this to guarantee the groups have the same differences (controls for confounding variables)  If your number is called, you will be a part of the experimental group

Experimental Group  Group implies people  People who receive the independent variable  Independent Variable: The "thing" that the experimental group gets that the control group does not get Mint

Control Group  Group implies people  The control group receives either nothing or a placebo So you can compare the results  Placebo: something given to the control group so they are confused if they received the independent variable NO MINT Placebo video (2:57) Placebo video

Dependent Variable  What is being measured How many words you remembered

Single Blind vs. Double Blind  The participants don’t know which group they are in *Minimizes participants acting differently *If you know you received the caffeine, you might act more focused during the test  BOTH the participants and the experimenter do not know if the participants received the independent variable or placebo *Eliminates experimenter bias, information is recorded fairly *No unconscious hints

Constant Variables  All the things that stayed the same How large the mint was How long you stared at the words How long you were given to recall the words

Operational Definitions  The details that allow someone else to replicate the study  If its not your exact directions, then its not your study

Confounding Variables  What else could cause the results to happen but it wasn’t your independent variable?  In our case, what else would cause someone to have good short term memory but it wasn’t the mint?

Validity and Reliability  Valid Does it accurately measure what you want to measure?  Reliable Is it consistent? If another researcher conducted the same study, would they get similar results? Research can be reliable without being valid!