## Longley's Economic Regression Data

### Description

A macroeconomic data set which provides a well-known example for a
highly collinear regression.

### Usage

longley

### Format

A data frame with 7 economical variables, observed yearly from 1947 to
1962 (*n=16*).

`GNP.deflator`

GNP implicit price deflator (*1954=100*)

`GNP`

Gross National Product.

`Unemployed`

number of unemployed.

`Armed.Forces`

number of people in the armed forces.

`Population`

‘noninstitutionalized’ population
*≥* 14 years of age.

`Year`

the year (time).

`Employed`

number of people employed.

The regression `lm(Employed ~ .)`

is known to be highly
collinear.

### Source

J. W. Longley (1967)
An appraisal of least-squares programs from the point of view of the
user.
*Journal of the American Statistical Association* **62**,
819–841.

### References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
*The New S Language*.
Wadsworth & Brooks/Cole.

### Examples

require(stats); require(graphics)
## give the data set in the form it is used in S-PLUS:
longley.x <- data.matrix(longley[, 1:6])
longley.y <- longley[, "Employed"]
pairs(longley, main = "longley data")
summary(fm1 <- lm(Employed ~ ., data = longley))
opar <- par(mfrow = c(2, 2), oma = c(0, 0, 1.1, 0),
mar = c(4.1, 4.1, 2.1, 1.1))
plot(fm1)
par(opar)