Descriptive Statistics
Least Squares Regression
Analyzing Departures from Linearity
Residuals :
**Residual=y-y hat
Vocabulary
Vocabulary
Residuals:The left-over vertical variation in the response variable (y) from the LSRL**
Residual Plot:A scatter plot of the residuals plotted against the explanatory variable and is used to determine if a linear model is appropriate for this data**
y=actual value
y hat=predicted value
Vocabulary
....% of the variation in the response(y) that is explained by the explanatory variable(x)
r^2(coefficient of determination): the proportion of variation in the values of y that can be explained by the values of x**
standard deviation of the residuals: "typical" or "average prediction error**
the typical prediction error is .... units
influential observation:a point that when removed, changes the relationship between two quantitative variables dramatically**
high-leverage point: is a point that has a substantially larger or smaller x-value compared to the other observations**
Statics for Two Categorical Variables
Representing the Relationship Between Two Quantitative Variables
Representing Two Categorical Variables
Frequency Table:a table that show frequency counts for a categorical variable**
Contingency Table/Two-Way Table: a table that is useful for examining a relationship between categorical variable**
Independence
Association
Joint Relative Frequency
bar graph
pie graph
mosaic plots
Marginal Relative Frequency: give the percent/proportion of individuals that have a specific value for one of the categorical variables**
Conditional Relative Frequency: give the percent/proportion of individuals that have a specific value of one categorical variable among individuals who share the same value of another categorical variable**
click to edit
Bivariate Data: the data collected on two variables where each value of one variable is paired with a value of the other variable.**
Scatterplot: a graphical display of bivariate quantitative data**
Explanatory Variable: the variable that explain/predict the value of the other variable **
Response Variable: the variable measured in study/focus of the study**