Nothing
## ----setup, include=FALSE, message=FALSE, warning=FALSE-----------------------
knitr::opts_chunk$set(
collapse = TRUE,
warning = FALSE,
message = FALSE,
fig.path = "figs/",
fig.retina = 3,
comment = "#>"
)
set.seed(5678)
## -----------------------------------------------------------------------------
library("logitr")
mnl_pref <- logitr(
data = yogurt,
outcome = 'choice',
obsID = 'obsID',
pars = c('price', 'feat', 'brand')
)
probs <- predict(mnl_pref)
head(probs)
## -----------------------------------------------------------------------------
probs <- predict(mnl_pref, returnData = TRUE)
head(probs)
## -----------------------------------------------------------------------------
data <- subset(
yogurt, obsID %in% c(42, 13),
select = c('obsID', 'alt', 'price', 'feat', 'brand'))
probs_mnl_pref <- predict(
mnl_pref,
newdata = data,
obsID = "obsID"
)
probs_mnl_pref
## -----------------------------------------------------------------------------
probs_mnl_pref <- predict(
mnl_pref,
newdata = data,
obsID = "obsID",
interval = "confidence",
level = 0.95
)
probs_mnl_pref
## -----------------------------------------------------------------------------
mnl_wtp <- logitr(
data = yogurt,
outcome = 'choice',
obsID = 'obsID',
pars = c('feat', 'brand'),
scalePar = 'price',
numMultiStarts = 10
)
probs_mnl_wtp <- predict(
mnl_wtp,
newdata = data,
obsID = "obsID",
interval = "confidence"
)
probs_mnl_wtp
## ----eval=FALSE---------------------------------------------------------------
# library("ggplot2")
#
# probs <- rbind(probs_mnl_pref, probs_mnl_wtp)
# probs$model <- c(rep("mnl_pref", 8), rep("mnl_wtp", 8))
# probs$alt <- rep(c("dannon", "hiland", "weight", "yoplait"), 4)
# probs$obs <- paste0("Observation ID: ", probs$obsID)
# ggplot(probs, aes(x = alt, y = predicted_prob, fill = model)) +
# geom_bar(stat = 'identity', width = 0.7, position = "dodge") +
# geom_errorbar(aes(ymin = predicted_prob_lower, ymax = predicted_prob_upper),
# width = 0.2, position = position_dodge(width = 0.7)) +
# facet_wrap(vars(obs)) +
# scale_y_continuous(limits = c(0, 1)) +
# labs(x = 'Alternative', y = 'Expected Choice Probabilities') +
# theme_bw()
## ----probabilities, echo=FALSE------------------------------------------------
knitr::include_graphics('probs.png')
## -----------------------------------------------------------------------------
outcomes_pref <- predict(
mnl_pref,
type = "outcome",
returnData = TRUE
)
head(outcomes_pref)
outcomes_wtp <- predict(
mnl_wtp,
type = "outcome",
returnData = TRUE
)
head(outcomes_wtp)
## -----------------------------------------------------------------------------
chosen_pref <- subset(outcomes_pref, choice == 1)
chosen_pref$correct <- chosen_pref$choice == chosen_pref$predicted_outcome
accuracy_pref <- sum(chosen_pref$correct) / nrow(chosen_pref)
accuracy_pref
chosen_wtp <- subset(outcomes_wtp, choice == 1)
chosen_wtp$correct <- chosen_wtp$choice == chosen_wtp$predicted_outcome
accuracy_wtp <- sum(chosen_wtp$correct) / nrow(chosen_wtp)
accuracy_wtp
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