Regression and Correlation Flashcards
1
Q
how do you use algebra to find the least squares coefficients a and b?
A
use total variability of x and y and find sample variances of x and y (learn equations)
2
Q
uses of the line of best fit
A
shows rate of change
makes predictions - be careful not to extrapolate beyond the range of the data
3
Q
excel line of best fit
A
data analysis, regression on a table of data
make a scatterplot and right click to add trendline and R squared
4
Q
correlation
A
how well a trend line fits (r)
r less than 0 is negative association
r more than 0 is positive association
- makes no distinction between response and explanatory variables
- both variables must be quantitative
- r values are between -1 and 1
- point near 0 are weak
- affected by outliers
has equations involving S
