slubst3100: Data for BST 3100 at Saint Louis University

#' Weight management piot study
#'
#' A dataset containing information about a pilot study for weight management in
#' individuals at risk for developing diabetes. The treatment group received 
#' additional weight management counseling from a physician's assitant during 
#' their regular doctor visits. The control group did not. The weight management
#' counseling lasted for 6 months, at which time weight was recorded. 
#' Participants returned for a 12-month visit in which weight was recorded 
#' again. Any missing data in the 6 or 12 month visits were imputed using 
#' baseline observation carried forward. All variables with \code{0m} suffix 
#' were recorded at baseline.
#'
#' @format A data frame with 50 rows and 22 variables: 
#'  \describe{
#'   \item{studyid}{Participant study identification number}
#'   \item{group}{Treatment group. \code{1} for counseling, \code{0} for 
#'   control} 
#'   \item{site}{Indicator of clinic location}
#'   \item{age}{Age in years}
#'   \item{gender}{Participant gender. \code{0} for male, \code{1} for female}
#'   \item{ethn}{Participant ethnicity. \code{0} for white, \code{1} for 
#'   African-American}
#'   \item{currsmoke}{Indicator for whether participant smoked cigarettes at the
#'   initiation of the study}
#'   \item{yrseduc}{Years of education completed}
#'   \item{height}{Height in inches}
#'   \item{wt0m}{Weight in pounds}
#'   \item{bmi}{Body mass index}
#'   \item{waist0m}{Waist circumference in inches}
#'   \item{sbp0m}{Systolic blood pressure}
#'   \item{dbp0m}{Diastolic blood pressure}
#'   \item{tchol0m}{Total cholesterol}
#'   \item{ldl0m}{LDL cholesterol}
#'   \item{hdl0m}{HDL cholesterol}
#'   \item{trig0m}{Blood triglycerides}
#'   \item{gluc0m}{Blood glucose}
#'   \item{wt6m}{Weight at 6-month follow up}
#'   \item{wt12m}{Weight at 12-month follow up}
#'   \item{keptoff}{Whether weight was kept off at 12-month follow up (Whether 
#'   12-month followup weight was less than baseline weight)}
#'  }
#' @source Data is described in \url{https://doi.org/10.1038/oby.2009.457}.
"tsai"