sm.sigma(x, y, rawdata = NA, weights = rep(1, length(y)), diff.ord = 2, ci = FALSE, model = "none", h = NA, ...)
sm.regression
and it need not be
set for direct calls of the function.sm.regression
and it need not be
set for direct calls of the function."constant"
then a test of constant variance over the covariates is performed
(only in the case of two covariates)sm.options
function, through a mechanism which limits their effect only to this
call of the function; the only one relevant for this function is
nbins
.sm.sigma2.compare
,
pseudo-residuals and, if appropriate, a confidence interval and
a p-value for the test of constant variance.sm.sigma2.compare
## Not run:
# with(airquality, {
# x <- cbind(Wind, Temp)
# y <- Ozone^(1/3)
# group <- (Solar.R < 200)
# sig1 <- sm.sigma(x[ group, ], y[ group], ci = TRUE)
# sig2 <- sm.sigma(x[!group, ], y[!group], ci = TRUE)
# print(c(sig1$estimate, sig1$ci))
# print(c(sig2$estimate, sig2$ci))
# print(sm.sigma(x[ group, ], y[ group], model = "constant", h = c(3, 5))$p)
# print(sm.sigma(x[!group, ], y[!group], model = "constant", h = c(3, 5))$p)
# print(sm.sigma2.compare(x[group, ], y[group], x[!group, ], y[!group]))
# })
# ## End(Not run)
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