Standard Scaler
Dataset T-Shirt
| SrNo | Height(in cms) | Weight(in kgs) | T Shirt Size |
|---|
| 1 | 158 | 58 | M |
| 2 | 158 | 59 | M |
| 3 | 158 | 63 | M |
| 4 | 160 | 59 | M |
| 5 | 160 | 60 | M |
| 6 | 163 | 61 | M |
| 7 | 160 | 64 | L |
| 8 | 163 | 64 | L |
| 9 | 165 | 61 | L |
| 10 | 165 | 62 | L |
| 11 | 165 | 65 | L |
| 12 | 168 | 62 | L |
| 13 | 168 | 63 | L |
| 14 | 168 | 66 | L |
| 15 | 170 | 63 | L |
| 16 | 170 | 64 | L |
| 17 | 170 | 68 | L |
Standard Scale
$$x_{scale}=\frac{x_i-\hat{x}}{stdv_x}$$
WITH CTE AS(
SELECT AVG(Height) AS HAvg, STDDEV(Height) AS HStdv, AVG(Weight) AS WAvg, STDDEV(Weight) AS WStdv
FROM Shop.TShirt
)
SELECT (Height - HAvg) / HStdv, (Weight - WAvg) / WStdv, Size FROM Shop.TShirt, CTE;
Method without CTE
SELECT
(Height - AVG(Height) OVER()) / STDDEV(Height) OVER(),
(Weight - AVG(Weight) OVER()) / STDDEV(Weight) OVER(),
Size
FROM Shop.TShirt;
Result
| SrNo | Height Scale | Weight Scale | T Shirt Size |
|---|
| 1 | -1.36131604 | -1.687951398 | M |
| 2 | -1.36131604 | -1.310383322 | M |
| 3 | -1.36131604 | 0.199888981 | M |
| 4 | -0.91194958 | -1.310383322 | M |
| 5 | -0.91194958 | -0.932815247 | M |
| 6 | -0.237899891 | -0.555247171 | M |
| 7 | -0.91194958 | 0.577457057 | L |
| 8 | -0.237899891 | 0.577457057 | L |
| 9 | 0.211466569 | -0.555247171 | L |
| 10 | 0.211466569 | -0.177679095 | L |
| 11 | 0.211466569 | 0.955025133 | L |
| 12 | 0.885516259 | -0.177679095 | L |
| 13 | 0.885516259 | 0.199888981 | L |
| 14 | 0.885516259 | 1.332593209 | L |
| 15 | 1.334882719 | 0.199888981 | L |
| 16 | 1.334882719 | 0.577457057 | L |
| 17 | 1.334882719 | 2.087729361 | L |