Chapter 14 Notes:
Inference for the Regression Model:
Step 1: Make a scatterplot
Step 2: Calculate the LSRL
Step 3: Identify outliers and influential points
Step 4: Calculate the correlation (r value)
The true regression line is written in the form: where a is the true x-intercept and b is the true slope.
Since s is unknown, we use s to estimate the value of s.
Note: (n – 2) is the degrees of freedom for the regression model.
To test whether or not there is a correlation between two quantitative variables, consider the slope of the regression line. If there is no correlation, the slope would be zero.
H0: b = 0
To test this hypothesis, compute the t statistic and P-value.