Runs survey::svyttest() for each outcome against a single binary grouping
variable, returning a tidy stacked tibble.
Value
A data frame with one row per outcome: outcome, group_var,
estimate (mean difference), statistic (t), df, p_value,
ci_lower, ci_upper.
Examples
if (FALSE) { # \dontrun{
survey_ttest(nptrends_y6_clean,
outcomes = c("LLLostAmt", "LLDelayWeeks1to6Median"),
group_var = "census_urban_area",
wt_var = "weight_year6plus")
} # }