1. Correlogram - ACF

2. Modeling for Forecast Forecast Data The Base Model Linear Trend Logistic Growth Others Models Look for a best approximation of the truth Forecasting Skill

3. Tools for Identifying a Best Model Review

4. Scatterplot and Correlation Coefficient - Review Y X

5. Correlogram as Model Identifier Timeplot Correlogram Models That Work

6. Autocorrelation Coefficient Definition: The correlation coefficient between Y t and Y (t-k) is called the autocorrelation coefficient at lag k and is denoted as  k. By definition,  0 = 1. Autocorrelation of a Random Series: If the series is random,  k = 0 for k = 1,...

7. Process Correlogram Lag, k kk 1 

8. Sample Autocorrelation Coefficient Sample Autocorrelation at lag k.

9. Standard Error of the Sample Autocorrelation Coefficient Standard Error of the sample autocorrelation if the Series is Random.

10. Z- Test of H 0 :  k = 0 Reject H 0 if Z 1.96

11. Test of Randomness Correlogram

12. Box-Ljung Q Statistic Definition

13. Sampling Distribution of Q BL (m) | H 0 H 0 :  1 =  2 =…  k = 0 Q BL (m) | H 0 follows a  2 (DF=m) distribution Reject H 0 if Q BL >  2 (95%tile)