Y’all Need a Runninback? By: Chris Torgalski & Jin Lee Y’all Need a Runninback?

What Is a Running back? A running back (RB) is a position on a football team. He usually lines up behind the linemen and the quarterback. His job is to take handoffs and pitches, occasionally go out for passes, and to block for the quarterback. He is also referred to as a tailback or halfback.

What We Want to Find Is there a relationship between loss of production and turning 30 years old for NFL running backs? Rushing Yards Rushing Touchdowns What is the average amount of Pro Bowls a running back makes?

How We Collected Data List of running drafted between 1995 and 2004 Assign each player a number Randomly generate a number until we had a list of 50 running backs that met our criteria without any repeats

1 Sample T-Test: Rushing Yards Difference (yards at 25-yards at 30) State Check 1)SRS 1) Stated random 2) Pop ≥ 10n 2) All RB in history ≥ 500 3)Normal pop or n ≥ 30 3) n = 50 Ho: µrushing difference = 0 Ha: µrushing difference > 0 Conditions met -> t distribution -> 1 sample t-test P(T > 3.457 l df = 49) = .00057 = 3.457 We reject the HO because our P-value of .00057 < alpha = .05. We have sufficient evidence that the rushing difference between age 25 and 30 for running backs is greater than 0. This means running rush for more yards at age 25 than they do at age 30.

1 Sample T-Interval: Rushing Yards Difference (yards at 25-yards at 30) State Check 1)SRS 1) Stated random 2) Pop ≥ 10n 2) All RB in history ≥ 500 3)Normal pop or n ≥ 30 3) n = 50 Conditions met -> t distribution -> 1 sample t-interval = (123.384 , 465.976) df= 49 We are 95% confident that the true difference in rushing yards between ages 25 and 30 is 123.384 and 465.976 yards.

Rushing Difference Graphs Shape: unimodal, symmetric Center: mean - 295.413 Spread: (-869,1566) Most running backs rush for about 295.413 more yards when they are 25 than when they are 30.

1 Sample T-Test: Rushing Touchdown Difference (touchdowns at 25- touchdowns at 30) State Check 1)SRS 1) Stated random 2) Pop ≥ 10n 2) All RB in history ≥ 500 3)Normal pop or n ≥ 30 3) n = 50 Ho: µtouchdown difference = 0 Ha: µtouchdown difference > 0 Conditions met -> t distribution -> 1 sample t-test P(T > 2.485 l df = 49) = .0082 = 2.485 We reject the HO because our P-value of .0082 < alpha = .05. We have sufficient evidence that the touchdown difference between age 25 and 30 for running backs is greater than 0. This means running rush for more touchdowns at age 25 than they do at age 30.

1 Sample T-Interval: Rushing Yards Difference (yards at 25-yards at 30) State Check 1)SRS 1) Stated random 2) Pop ≥ 10n 2) All RB in history ≥ 500 3)Normal pop or n ≥ 30 3) n = 50 Conditions met -> t distribution -> 1 sample t-interval = (.447338 , 4.23266) df= 49 We are 95% confident that the true difference in rushing touchdowns between ages 25 and 30 is .447338 and 4.23266 touchdowns.

Touchdown Difference Graphs Shape: unimodal, roughly symmetric Center: mean - 2.34 Spread: (-20,20) Most running backs score about 2.34 touchdowns more when they are 25 then when they are 30.

1 Sample T-Test: Pro Bowls Made State Check 1)SRS 1) Stated random 2) Pop ≥ 10n 2) All RB in history ≥ 500 3)Normal pop or n ≥ 30 3) n = 50 Ho: µpro bowls made = 1 Ha: µpro bowls made > 1 Conditions met -> t distribution -> 1 sample t-test P(T > 1.275 l df = 49) = .1 = 1.275 We fail to reject the HO because our P-value of .1 > alpha = .05. We have sufficient evidence that running backs make 1 Pro Bowl during their career in the NFL.

1 Sample T-Interval: Pro Bowls Made State Check 1)SRS 1) Stated random 2) Pop ≥ 10n 2) All RB in history ≥ 500 3)Normal pop or n ≥ 30 3) n = 50 Conditions met -> t distribution -> 1 sample t-intevral = (.838827 , 1.72117) df= 49 We are 95% confident that the true number of Pro Bowls that a running back makes during his career in the NFL is between .838827 and 1.72117 Pro Bowls.

Pro Bowls Made Graphs Shape: unimodal, right-skewed Center: median - 1 Spread: (0,5) Most running backs make about 1 Pro Bowl.

Rushing Yards Scatterplot Formula: RY@30 = .286(RY@25) + 300 Interpretation: rushing yards at 25 times .286 plus 300 = rushing yards at 30

Touchdown Scatterplot Formula: TD@30 = .116(TD@25) + 2.8 Interpretation: touchdowns at 25 times .116 plus 2.8 = touchdowns at 30

Who is this running back? Age 25 Stats Yards: 1298 Touchdowns: 12 Age 30 prediction Yards: 671.228 Touchdowns: 4.192 Adrian Peterson

Who is this running back? Age 25 Stats Yards: 1364 Touchdowns: 11 Age 30 prediction Yards: 690.104 Touchdowns: 4.076 Chris Johnson

Who is this running back? Age 25 Stats Yards: 1008 Touchdowns: 13 Age 30 prediction Yards: 588.288 Touchdowns: 4.308 BenJarvius Green-Ellis

Who is this running back? Age 25 Stats Yards: 1515 Touchdowns: 18 Age 30 prediction Yards: 733.29 Touchdowns: 4.888 Deangelo williams

Who is this running back? Age 25 Stats Yards: 1324 Touchdowns: 5 Age 30 prediction Yards: 678.664 Touchdowns: 3.38 Maurice Jones Drew

Who is this running back? Age 25 Stats Yards: 1042 Touchdowns: 7 Age 30 prediction Yards: 598.012 Touchdowns: 3.612 Steven Jackson

Application Running backs are better statistically at age 25 than they are at age 30. This means running backs should work to become productive earlier in their careers in order to obtain a large contract early. The player might want to work harder than planned at age 30 so that they can improve their production.

Bias/Error The running back got hurt during their season for being 25 or 30 The running back could have been a starter for one season and a backup for the other The offensive line could have been better one year than it is the other.

Conclusion/Opinion We would choose to have a running back age 25 on our team instead of a running back age 30 Running backs that are 25 score more touchdowns and gain more yards They will also be in the league longer due to younger age We found out running backs will make around one Pro Bowl in their career