REGR_SXX

REGR_SXX is an SQL function used in statistical analysis. It calculates the sum of the squares of the differences between the dependent variable's observed values and its mean, allowing further computation of variance or standard deviation.

REGR_SXX(Y, X)

  • y: This is the dependent variable in the linear regression model. It is typically a column name indicating the response, or output, variable whose values you seek to explain or predict.
  • x: This is the independent variable in the linear regression model. It is typically a column name representing the predictor, or input, variable that explains or predicts the values of the dependent variable Y.

Example

SELECT
REGR_SXX(salary, commission_pct) AS "Regr_Sxx"
FROM employees;

Output

Regr_Sxx
------------
4.256389877

Explanation

In the provided example, REGR_SXX(salary, commission_pct) computes the covariance of the salary and commission percentage of employees. Covariance is a measure of how much two random variables vary together. It is easy to calculate the covariance between two variables using the REGR_SXX function in SQL.

REGR_SXX(Y, X)

  • y: This is the dependent variable in the regression equation. It is a numeric or a non-null input column in the database from which the function will establish a relationship.
  • x: This is the independent variable in the regression equation. It represents a numeric or non-null input column in the database that influences a dependent variable (Y).

Example

SELECT REGR_SXX(work_experience, salary)
FROM Employee;

Output

4.67

Explanation

In the provided example, the REGR_SXX() function is applied on work_experience and salary columns of the Employee table. This function calculates the sum of squares of differences from the mean for work_experience (the dependent variable) per unit of salary (the independent variable). The resultant value, 4.67, indicates the variability of work_experience per unit of salary.

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