# ecq: Lag shape constructors

## Description

Lag shape constructors to be used in model formulas.

## Usage

ecq(x, a, b, x.group = NULL, nlag = NULL)
qd(x, a, b, x.group = NULL, nlag = NULL)
ld(x, a, b, x.group = NULL, nlag = NULL)
gam(x, a, b, x.group = NULL, nlag = NULL)

## Arguments

x

The name of the variable.

nlag

The number of lags considered. If `NULL`

or more than 2/3 of the sample size, it is set equal to 2/3 of the sample size.

x.group

The name of the group factor (optional).

## References

A. Magrini (2020). A family of theory-based lag shapes for distributed-lag linear regression. To be appeared on *Italian Journal of Applied Statistics*.

## Examples

# NOT RUN {
data(industry)
# example in linear regression
m1 <- lm(Consum ~ -1+Region+ecq(Job,0,5,x.group=Region), data=industry)
m2 <- lm(Consum ~ -1+Region+gam(Job,0.85,0.2,x.group=Region), data=industry)
# }