Population Define:

Parameter Define:

Define: A math calculation performed on sample data Term: Define: A math calculation performed on sample data

Term: Define: A small group of the total observational units used to gather data

Term: Sample Bias Define: A sample which overrepresents some parts of the population while under representing others.

Term: Observational Study Define: Researchers passively observe and record information on the observational units. ** You can NOT draw a cause-and-effect conclusion from observational studies!!!

Example: If 95% of high school students in a AAA driving school program have fewer accidents during their first year of driving, would you conclude that AAA driving school was responsible for this?

Example: You identify, in a sample of adults, who eats apples and who does not. You follow them for 6 months recording the number of doctor’s visits. If apple eaters had less doctor visits, would you conclude that eating apples was responsible for this?

There were two variables in the apple eating study There were two variables in the apple eating study. Variable 1: Adults who ate apples Variable 2: Number of doctor visits I want to study apple eaters. I want to see if they have fewer doctor visits. Explanatory variable: variable whose effect you want to study Response variable: variable you suspect is affected by the other variable

I want to study apple eaters I want to study apple eaters. I want to see if they have fewer doctor visits. Group 1 Observational units Compare results Group 2 explanatory var. response var. Adults who Number of ate apples doctor visits

Observational Studies do NOT look at all possible effects on variables Observational Studies do NOT look at all possible effects on variables. These unmonitored variables are called lurking variables. A lurking variable which effects the response variable but is invisible in the explanatory variable is called a confounding variable. “What are some variables not looked at but might have effected the rsponse?” Name an example of a confounding variable in the apple eater study.