Compute the Box–Pierce or Ljung–Box test statistic for examining the null hypothesis of independence in a given time series. These are sometimes known as ‘portmanteau’ tests.

```
ljung_box(x, lag = 1, dof = 0, ...)
box_pierce(x, lag = 1, dof = 0, ...)
portmanteau_tests
```

## Arguments

- x
A numeric vector

- lag
The number of lag autocorrelation coefficients to use in calculating the statistic

- dof
Degrees of freedom of the fitted model (useful if x is a series of residuals).

- ...
Unused.

## Value

A vector of numeric features for the test's statistic and p-value.

## Examples

```
ljung_box(rnorm(100))
#> lb_stat lb_pvalue
#> 0.4201284 0.5168730
box_pierce(rnorm(100))
#> bp_stat bp_pvalue
#> 6.774436858 0.009247266
```