walsh.cottonprice | R Documentation |
Acres and price of cotton 1910-1943
A data frame with 34 observations on the following 9 variables.
year
year, numeric 1910-1943
acres
acres of cototn (1000s)
cotton
price per pound (cents) in previous year
cottonseed
price per ton (dollars) in previous year
combined
cotton price/pound + 1.857 x cottonseed price/pound (cents)
index
price index, 1911-1914=100
adjcotton
adjusted cotton price per pound (cents) in previous year
adjcottonseed
adjusted cottonseed price per ton (dollars) in previous year
adjcombined
adjusted combined price/pound (cents)
The 'index' is a price index for all farm commodities.
R.M. Walsh (1944). Response to Price in Production of Cotton and Cottonseed, Journal of Farm Economics, 26, 359-372. https://doi.org/10.2307/1232237
## Not run:
library(agridat)
data(walsh.cottonprice)
dat <- walsh.cottonprice
dat <- transform(dat, acres=acres/1000) # convert to million acres
percentchg <- function(x){ # percent change from previous to current
ix <- 2:(nrow(dat))
c(NA, (x[ix]-x[ix-1])/x[ix-1])
}
# Compare percent change in acres with percent change in previous price
# using constant dollars
dat <- transform(dat, chga = percentchg(acres), chgp = percentchg(adjcombined))
with(dat, cor(chga, chgp, use='pair')) # .501 correlation
libs(lattice)
xyplot(chga~chgp, dat, type=c('p','r'),
main="walsh.cottonprice",
xlab="Percent change in previous price", ylab="Percent change in acres")
## End(Not run)
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