```ts
linreg(value: number, length: number): number | null
```

Performs linear regression analysis on a series of data points to determine the linear trend line.

## Parameters

- `value`: The current value to be included in the linear regression calculation.
- `length`: The number of points to consider in the calculation.

## Returns

- The y-value of the linear regression line corresponding to the latest data point if sufficient data is available; otherwise, `null`.

## Summary

The `linreg` function calculates the linear regression line for a specified set of data points. Linear regression is a fundamental statistical method used to understand the relationship between variables, often used in financial markets to predict future values based on past trends. This function considers the current value and the specified length of previous data points to compute the line. It calculates the slope and intercept of the linear regression line and returns the y-value corresponding to the position of the latest data point. This is particularly useful in identifying and following market trends.

*Note: The function requires a sufficient number of data points to perform the calculation. If the number of data points is less than the specified length, the function returns `null`, indicating that the regression analysis cannot be performed accurately.*
