mirror of
https://github.com/Llewellynvdm/php-ml.git
synced 2024-11-29 16:24:05 +00:00
81 lines
1.3 KiB
Markdown
81 lines
1.3 KiB
Markdown
# Statistic
|
||
|
||
Selected statistical methods.
|
||
|
||
## Correlation
|
||
|
||
Correlation coefficients are used in statistics to measure how strong a relationship is between two variables. There are several types of correlation coefficient.
|
||
|
||
### Pearson correlation
|
||
|
||
Pearson’s correlation or Pearson correlation is a correlation coefficient commonly used in linear regression.
|
||
|
||
Example:
|
||
|
||
```
|
||
use Phpml\Math\Statistic\Correlation;
|
||
|
||
$x = [43, 21, 25, 42, 57, 59];
|
||
$y = [99, 65, 79, 75, 87, 82];
|
||
|
||
Correlation::pearson($x, $y);
|
||
// return 0.549
|
||
```
|
||
|
||
## Mean
|
||
|
||
### Arithmetic
|
||
|
||
Example:
|
||
|
||
```
|
||
use Phpml\Math\Statistic\Mean;
|
||
|
||
Mean::arithmetic([2, 5];
|
||
// return 3.5
|
||
|
||
Mean::arithmetic([0.5, 0.5, 1.5, 2.5, 3.5];
|
||
// return 1.7
|
||
```
|
||
|
||
## Median
|
||
|
||
Example:
|
||
|
||
```
|
||
use Phpml\Math\Statistic\Mean;
|
||
|
||
Mean::median([5, 2, 6, 1, 3, 4]);
|
||
// return 3.5
|
||
|
||
Mean::median([5, 2, 6, 1, 3]);
|
||
// return 3
|
||
```
|
||
|
||
## Mode
|
||
|
||
Example:
|
||
|
||
```
|
||
use Phpml\Math\Statistic\Mean;
|
||
|
||
Mean::mode([5, 2, 6, 1, 3, 4, 6, 6, 5]);
|
||
// return 6
|
||
```
|
||
|
||
## Standard Deviation
|
||
|
||
Example:
|
||
|
||
```
|
||
use Phpml\Math\Statistic\StandardDeviation;
|
||
|
||
$population = [5, 6, 8, 9];
|
||
StandardDeviation::population($population)
|
||
// return 1.825
|
||
|
||
$population = [7100, 15500, 4400, 4400, 5900, 4600, 8800, 2000, 2750, 2550, 960, 1025];
|
||
StandardDeviation::population($population)
|
||
// return 4079
|
||
```
|