Average Estimation Error for Causal Forecasting model based on headcount, what is the MEE with step by step of how to find the predicted call volume (linear regression) and absolute error.

Ft=aAt-1+(1-a) Ft-1 SUMMARY OUTPUT Actual Employee Call Head Regression Statistics Year Month volume Count Notes Multiple R 0.973375551 2014 Jan 24,015 62, 120 R Square 0.947459963 2014 Feb 25,203 62, 152 Adjusted R S 0.94417621 2014 Mar 23,589 62, 138 Standard Erro 643.24177 2014 Apr 27,454 68,343 Centex corporation acquired 4/1/2014 Observations 18 2014 May 28, 120 68, 120 2014 Jun 28,321 67,987 Dental insurance plan changed effective 7/1/2014 ANOVA 2014 Jul 29,021 67,956 df SS MS F gnificance F 2014 Aug 26,954 65,342 Printer division sold to Arconet Corporation 8/1/2014 Regression 1 119382026.8 1.19E+08 288.5297 1.17E-11 2014 Sep 26,456 65,380 Residual 16 6620159.595 413760 2014 Oct 27, 120 65,432 Major tax law changes signed into law by U.S. President Total 17 126002186.4 2014 Nov 26,954 65,423 2014 Dec 27,321 65,650 Year-end bonuses announced on 12/10/2014 Coefficients Standard Error t Stat P-value Lower 95%Upper 95% 2015 Jan 26,456 65,620 Intercept -11710.0159 2340.497776 -5.00322 0.00013 -16671.6 -6748.38 2015 Feb 27,450 65,610 X Variable 1 0.586441011 0.034524635 16.98616 1.17E-11 0.513252 0.65963 2015 Mar 31,435 75,231 Paxton Enterprises acquired 3/15/2015 2015 Apr 33, 124 75,201 2015 May 32,432 74,978 slope 0.586441011 2015 Jun 31,901 75,012 New employee insurance deductions in effect starting 7/1/2015 intercept -11710.0159 2015 Jul 35,205.26 80,000 y 35,205.26