movies data frame: title opening budget isstar issummer 1 AirForceOne 37.132 85.00 Star Summer 2 BatmanandRobin 42.870 110.00 Star Summer 3 Bean 2.255 22.00 NoStar NoSummer 4 ConAir 24.131 75.00 Star Summer 5 Contact 20.584 90.00 Star Summer 6 CopLand 13.510 15.00 Star Summer 7 ChasingAmy 1.642 0.25 NoStar NoSummer 8 ConspiracyTheory 19.313 75.00 Star Summer 9 FathersDay 8.767 90.00 Star NoSummer 10 TheDevilsAdvocate 12.170 57.00 Star NoSummer 11 TheDevilsOwn 18.063 80.00 Star NoSummer 12 FaceOff 23.387 80.00 Star Summer 13 TheFifthElement 17.031 90.00 NoStar NoSummer 14 TheGame 14.337 50.00 NoStar NoSummer 15 Jane 11.094 50.00 NoStar Summer 16 GeorgeoftheJungle 22.878 55.00 NoStar Summer 17 GoodBurger 7.058 9.00 NoStar Summer 18 GrossPointBlank 6.870 15.00 NoStar NoSummer 19 Hercules 21.454 70.00 NoStar Summer 20 KisstheGirl 13.215 27.00 NoStar NoSummer 21 TheLostWorld 92.729 73.00 NoStar NoSummer 22 MeninBlack 84.133 90.00 NoStar Summer 23 Metro 18.734 55.00 NoStar NoSummer 24 Mimic 7.818 25.00 NoStar Summer 25 ThePeaceMaker 12.311 50.00 Star NoSummer 26 PrivateParts 14.616 20.00 NoStar NoSummer 27 TheSaint 16.278 70.00 Star NoSummer 28 SoulFood 11.197 7.00 NoStar NoSummer 29 Speed2 16.158 110.00 Star NoSummer 30 Spawn 21.210 40.00 NoStar Summer 31 Volcano 14.581 90.00 NoStar NoSummer 32 187 2.912 23.00 NoStar Summer with_dummy_vars data frame: title opening budget star_dum sum_dum 1 AirForceOne 37.132 85.00 1 1 2 BatmanandRobin 42.870 110.00 1 1 3 Bean 2.255 22.00 0 0 4 ConAir 24.131 75.00 1 1 5 Contact 20.584 90.00 1 1 6 CopLand 13.510 15.00 1 1 7 ChasingAmy 1.642 0.25 0 0 8 ConspiracyTheory 19.313 75.00 1 1 9 FathersDay 8.767 90.00 1 0 10 TheDevilsAdvocate 12.170 57.00 1 0 11 TheDevilsOwn 18.063 80.00 1 0 12 FaceOff 23.387 80.00 1 1 13 TheFifthElement 17.031 90.00 0 0 14 TheGame 14.337 50.00 0 0 15 Jane 11.094 50.00 0 1 16 GeorgeoftheJungle 22.878 55.00 0 1 17 GoodBurger 7.058 9.00 0 1 18 GrossPointBlank 6.870 15.00 0 0 19 Hercules 21.454 70.00 0 1 20 KisstheGirl 13.215 27.00 0 0 21 TheLostWorld 92.729 73.00 0 0 22 MeninBlack 84.133 90.00 0 1 23 Metro 18.734 55.00 0 0 24 Mimic 7.818 25.00 0 1 25 ThePeaceMaker 12.311 50.00 1 0 26 PrivateParts 14.616 20.00 0 0 27 TheSaint 16.278 70.00 1 0 28 SoulFood 11.197 7.00 0 0 29 Speed2 16.158 110.00 1 0 30 Spawn 21.210 40.00 0 1 31 Volcano 14.581 90.00 0 0 32 187 2.912 23.00 0 1 Start: AIC=186.07 opening ~ budget + star_dum + sum_dum Df Sum of Sq RSS AIC - sum_dum 1 281.5 8634.8 185.13 8353.3 186.07 - star_dum 1 1053.5 9406.7 187.87 - budget 1 3582.2 11935.5 195.49 Step: AIC=185.13 opening ~ budget + star_dum Df Sum of Sq RSS AIC 8634.8 185.13 - star_dum 1 977.6 9612.4 186.56 - budget 1 3679.0 12313.9 194.49 Call: lm(formula = opening ~ budget + star_dum, data = with_dummy_vars) Residuals: Min 1Q Median 3Q Max -24.528 -9.042 -1.756 2.527 60.378 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 3.3282 6.2444 0.533 0.59811 budget 0.3976 0.1131 3.515 0.00147 ** star_dum -13.1534 7.2593 -1.812 0.08036 . --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 17.26 on 29 degrees of freedom Multiple R-squared: 0.2988, Adjusted R-squared: 0.2504 F-statistic: 6.178 on 2 and 29 DF, p-value: 0.00582