ENGDAT2 Flashcards
Type of graph that can be used to show the relationship between two variables
Scatterplot
Used to measure the strength of the association (linear relationship) between two variables.
Correlation
Variable we wish to explain or predict
Dependent Variable
Variable used to predict or explain the dependent variable
Independent Variable
Equation of Simple Linear Regression Model
Y = A + BX or Yi = b0 + b1Xi
Differentiate SST, SSR, and SSE.
SST (Total Sum of Squares) = Total Variation
SSR (Regression Sum of Squares) = Explained Variation/Outcome
SSE (Error Sum of Squares) = Unexplained Variation/Outcome
Portion of the total variation in the dependent variable that is explained by variation in the independent variable
Coefficient of Determination (r^2) wherein 0 <= r^2 <= 1
If r^2 = 1, what does it imply?
Perfect linear relationship between X and Y. 100% of the variation in Y is explained by the variation in X.
if r^2 = 0, what does it imply?
No linear relationship between X and Y. Value of Y does not depend on X.
Standard deviation of the variation of observations around the regression line
Standard Error of Estimate (S)
Assumptions of Regression L.I.N.E
Linearity - Relationship between X and Y is linear
Independence of Errors - Error values are statistically independent
Normality of Error - Error values are normally distributed for any given value of X
Equal Variance - the probability distribution of the errors has constant variance.
Difference between observed and predicted value
Residual
Process that checks assumptions of regression by examining residuals
Residual Analysis
Exists if residuals in one time period are related to residuals in another period. Violates regression assumption that residuals are random and independent.
Autocorrelation
Test Statistic used to test for autocorrelation
Durbin-Watson
Original hypothesis that motivates the experiment
Conjecture
Test performed to investigate the conjecture
Experiment
Statistical analysis of the data from the experiment
Analysis
What has been learned about the original conjecture from the experiment
Conclusion
Sequence of Activities for every experiment
- Conjecture
- Experiment
- Analysis
- Conclusion
Level of the factor
Treatments