The goal of this unit is to calculate baseball statistics or to show you the relationship between baseball and math.

A strike occurs when a pitcher throws the ball and the batter fails to hit the ball properly. When this happens three times, it is a strikeout (K) and the batter must leave.

A base on balls or walk (BB) occurs when a pitcher throws the ball out of the strike zone four times. When this happens, the batter can move to the first base.

The strikeout to walk ratio is therefore a ratio measuring how good a pitcher is. A good pitcher wants to maximize the number of strikeouts and minimize the number of walks.

Suppose the strikeout to walk ratio of a pitcher is 3.40.

3.40 = 340 / 100 = 34 / 10 = 17 / 5 = K/BB

17 is the number of strikeouts and 5 is the number of walks the pitcher has.

Every time the pitcher allows 5 walks, he generates 17 strikeouts.

An at-bat (AB) occurs every time a batter is at the plate trying to hit the ball. This can result in a hit, strikeout, ...

Do not confuse at-bat with plate appearance (PA). Plate appearance happens every time the player is at the plate regardless of the result.

A home run (HR) occurs when the player successfully reaches all bases (first base, second base, third base, and home base).

The at-bat per home run is therefore a ratio measuring how good a batter is at reaching the home plate. A good batter wants to have as many home runs as possible.

Suppose a batter reaches the home plate 50 times in 1500 at-bats.

AB/HR = 1500/50 = 30

This means that the player hits a home run every 30 at-bats.

On-base percentage is a measure of how frequently a batter reaches base per plate appearance.

A batter reaches base every time there is a hit, walk, or hit by pitch.

Plate appearance occurs every time there is a walk, at-bat, hit by pitch, or sacrifice.

A hit occurs when the batter reaches a base after hitting the ball either into the infield or the outfield.

A hit by pitch occurs when a batter is struck by the ball without swinging at it and is awarded first base as a result.

A sacrifice occurs when the batter purposely strikes the ball into the air or tap the ball lightly in order to give a teammate the opportunity to score.

Let H = hits, BB = walks, HBP = hit by pitch, AB = at-bats, and SF = sacrifices.

OBP = (H + BB + HBP) / (AB + BB + HBP + SF)

Suppose in baseball game, a player has the following statistics. What is the player's on-base percentage?

H = 3, BB = 1, HBP = 0, AB = 5, SF = 1

OBP = (3 + 1 + 0) / (5 + 1 + 0 + 1)

OBP = (4) / (7)

OBP = 0.57

Batting Average

This lesson will explain the meaning of batting average and show you how to use a simple formula to get it. It is a measurement of how well a player hits.

Baserunning Average

This lesson will explain the meaning of baserunning average and show you how to use a simple formula to get it. It is a measurement of how well a player steal bases.

Earned Run Average

This lesson will explain the meaning of earned run average and show you how to use a simple formula to get it. It is a measurement of how well a pitcher is at not allowing runs in the game.

Slugging percentage

This lesson will explain the meaning of slugging percentage (SLG) and show you how to use a simple formula to get it. It is a measurement of how well a player bats.

Fielding percentage

This lesson will explain the meaning of fielding percentage and show you how to use a simple formula to get it. It is a measurement of how well a fielder is at creating putouts.

Games back

This lesson will explain the meaning of games back and show you how to use a simple formula to get it. It is a measurement of how many games behind other teams are compared to the first place team.

This lesson will explain the meaning of batting average and show you how to use a simple formula to get it. It is a measurement of how well a player hits.

Baserunning Average

This lesson will explain the meaning of baserunning average and show you how to use a simple formula to get it. It is a measurement of how well a player steal bases.

Earned Run Average

This lesson will explain the meaning of earned run average and show you how to use a simple formula to get it. It is a measurement of how well a pitcher is at not allowing runs in the game.

Slugging percentage

This lesson will explain the meaning of slugging percentage (SLG) and show you how to use a simple formula to get it. It is a measurement of how well a player bats.

Fielding percentage

This lesson will explain the meaning of fielding percentage and show you how to use a simple formula to get it. It is a measurement of how well a fielder is at creating putouts.

Games back

This lesson will explain the meaning of games back and show you how to use a simple formula to get it. It is a measurement of how many games behind other teams are compared to the first place team.

OPS is equal to on-base percentage + slugging percentage.

The higher the OPS is, the more value is put on the hitter.

Baseball is probably America's favorite game. You will hear baseball fans talking about a pitcher's ERA, a hitter's batting average, and some other important statistics in baseball.

The numbers you get have a mathematical meaning that tells you how well the players are doing. Once you understand baseball stats or the meaning of these terms, it is easier to keep track of what is going on in the game. Furthermore, it is much more fun to watch the game as you keep track of these stats. Lastly, analysts, coach, fans, and owners can use these stats to determine how great or valuable a team or a player is.

I explain these terms in here and most importantly, I show you how it relates to math.

Look for baseball statistics in baseball cards and in newspapers.