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Obtain a confidence interval from coefficient draws

Source: R/utils.R
ci.Rd

Returns a data frame with the columns 'mean', 'lower', and 'upper' reflecting the mean and lower and upper bounds of a confidence interval (quantiles) for every column in a data frame of draws

Usage

ci(df, level = 0.95)

Arguments

df

A data frame of draws with all numeric columns.

level

The sensitivity of the computed confidence interval (CI). Defaults to level = 0.95, reflecting a 95% CI.

Value

A data frame with one row for each column in df and the columns mean, lower, and upper, reflecting the mean and the lower and upper bounds of the confidence interval for each of those columns.

Examples

library(logitr)

# Estimate a preference space model
mnl_pref <- logitr(
  data    = yogurt,
  outcome = "choice",
  obsID   = "obsID",
  pars    = c("price", "feat", "brand")
)
#> Running model...
#> Done!

# Obtain 10,000 draws of parameters from model
coefs <- coef(mnl_pref)
covariance <- vcov(mnl_pref)
coef_draws <- as.data.frame(MASS::mvrnorm(10^4, coefs, covariance))

# Compute a confidence interval
ci(coef_draws, level = 0.95)
#>                    mean      lower      upper
#> price        -0.3668163 -0.4133064 -0.3201620
#> feat          0.4895479  0.2535552  0.7233242
#> brandhiland  -3.7151683 -3.9959753 -3.4309621
#> brandweight  -0.6414737 -0.7465685 -0.5361505
#> brandyoplait  0.7355967  0.5772076  0.8900850