The "math" contained within this blog ranges from the purely mathematical equation (e.g., takt time, average) to metrics (e.g., inventory turns, order fill) to pseudo-mathematical (e.g., change management, waste elimination effectiveness) to concept introduction (e.g., hypothesis tests) to data and math integrity considerations (e.g., gauge repeatability and reproducibility, measurement system validation). So, the reader is bound to run into formulas, symbols, and mathematical definitions.
We try to keep things as simple as possible. Nevertheless, the following table of mathematical symbols may serve as a handy reference.
Category
|
Symbol
|
Name
|
Definition
|
Example
|
Basic Math
|
= |
equals sign
|
equality
|
7 = 4+3 |
> |
strict inequality
|
greater than
|
7>6 |
< |
strict inequality
|
less than
|
7<8 |
≥ |
inequality
|
greater than or equal to
|
7≥6 |
≤ |
inequality
|
less than or equal to
|
7≤8 |
( ) |
parentheses
|
calculate expression inside first
|
3x(4+1) = 15 |
[] |
brackets
|
calculate expression inside first
|
[(3+2)x(2+5)]=35 |
+ |
plus sign
|
addition
|
3+2=5 |
- |
minus sign
|
subtraction
|
5-2=3 |
x |
times sign
|
multiplication
|
3x5=15 |
/ |
division slash
|
division
|
8/2=4 |
¯ |
horizontal line
|
division/fraction
|
 |
ab |
power
|
exponent
|
32=9 |
√ |
square root
|
|
√9=±3 |
Algebra
|
{ } |
braces
|
set
|
|
 |
floor brackets
|
rounds number to lower integer
|
 |
|
ceiling brackets
|
rounds number to upper integer
|
 |
|
nearest integer
|
rounds positive number to nearest integer
|
|
|x| |
single vertical bar
|
absolute value
|
|-3|=3 |
(a,b) |
open interval
|
|
|
∑ |
sigma
|
summation – sum of all values in a range or series
|
 |
Probability and statistics
|
P(A) |
probability function
|
probability of event A
|
P(A)=0.7 |
P(A∩B) |
probability of events intersection
|
probability of events A and B
|
P(A∩B)=0.7 |
P(AUB) |
probability of events union
|
probability of events A or B
|
P(AUB)=0.7 |
P(A|B) |
conditional probability
|
probability of event A given event B occurred
|
P(A|B)=0.5 |
 |
overbar or bar
|
sample average
|
 |