Test the significance of the best subset regression model using a=0.05 what is the right critical value?

Screen Size RAM Memory Hard drive USB Ports Weight Brand 13.3 4 500 1.9 Toshiba 13.3 640 3 3.2 Toshiba 11.6 128 2 2.3 Apple 18.4 640 9.7 Toshiba 18.4 500 9.7 Toshiba 14 500 2 5 Toshiba 13.3 500 2 4.7 Toshiba 14 320 4.9 HP SONWA 13.3 128 3 Apple 17.3 640 6.7 HP 15.6 320 5.5 Toshiba 15.6 640 6.5 Toshiba 15.6 6 640 5.9 HP 15.6 6 640 6.5 Toshiba 14.5 320 5.2 HP 15.6 320 5.5 HP 17.3 1000 6.9 HP 17.3 500 6.4 Toshiba 13.3 320 4.5 Apple 15.4 750 5.6 Apple 13.3 2 250 5.4 Toshiba 16 6 640 5.8 Toshiba 15.6 6 640 5.9 HP 17.3 6 640 6.7 Toshiba 13.3 2 256 JWNNWWWNWWNNNNA 2.9 Apple 17 750 6.6 Apple 15.6 500 5.4 HP 14 320 4.9 HP 14 640 5.4 Toshiba 15.6 500 5.2 HF 15.6 4 640 5.8 Toshiba 15.6 640 5.5 HP 15.6 4 250 6 Toshiba 15.4 500 5.6 Apple WAWNNW 15.6 500 6 HP 15.6 750 5.8 HP 15.6 320 5.5 HP 18.4 500 3 9.7 Toshiba 15.6 500 2 5.5 Toshiba 14 500 5 HP 17.3 500 7.6 Toshiba 13.1 250 5.1 HP 13.3 4 500 4.5 Apple 15.6 500 5.5 HP 15.6 320 5.9 HP 13.3 AWNWA 128 2.9 Apple 15.6 250 5.5 Toshiba 14 500 ANWWNWWWNNNWWNNWN 5 Toshiba 15.6 4 500 5.5 HP 15.6 320 5.6 HP 15.6 4 500 5.5 HP 17.3 6 640 7.9 Toshiba 15.6 4 500 5.9 HP 17.3 500 6.1 HP 15.6 640 5.8 Toshiba 17.3 1500 7.8 HP 17.3 1000 4 7.7 HP 13.3 250 4.7 Apple 14 640 5.4 Toshiba 15.6 500 5.8 Toshiba NWWWNN 15.6 4 500 5.4 HP 15.6 8 750 5.9 Toshiba 11.6 64 2.3 Apple