Unit 2 Flashcards
Define: Response variable.
Measures the outcome of a study, also called the dependent variable.
Define: Explanatory variable.
Attempts to explain the observed outcome of the study, also called the independent variable.
When do we use scatterplots?
To look at relationships between two quantitative variables.
- Explanatory variable along the x-axis.
- Response variable along the y-axis.
Define: Correlation coefficient (r).
Measures the direction and strength of a linear relationship, ranging from -1 to +1.
- -1 = very strong negative correlation.
- 0 = no correlation.
- +1 = very strong positive correlation.
Define: Positive association.
When X increases, so does Y. (Looks like an upward slope).
Define: Negative association.
When X increases, Y decreases. (Looks like a downward slope).
Define: No association.
No pattern seen, values appear random.
Extrapolation:
Finding a range of values not included in our study.
Residual:
The difference between an observed value of the response and the value predicted by the regression line.
Residual= observed y - predicted y.
An outlier is an observation with an extremely large ______.
Residual.
Points that are outliers in the “y” direction are usually known as ________.
Outliers.
Points that are outliers in the “x” direction are usually known as ________.
Influential observations.
Define: Lurking variable.
A variable that is not being studied, but may influence the relationship between the two variables being studied.
