The function best() takes two arguments: the 2-character abbreviated name of a state and an outcome name. The function reads the outcome-of-care-measures.csv file and returns a character vector with the name of the hospital that has the best (i.e. lowest) 30-day mortality for the specified outcome in that state. The hospital name is the name provided in the Hospital.Name variable. The outcomes can be one of “heart attack”, “heart failure”, or “pneumonia”. Hospitals that do not have data on a particular outcome should be excluded from the set of hospitals when deciding the rankings.
Handling ties: If there is a tie for the best hospital for a given outcome, then the hospital names are sorted in alphabetical order and the first hospital in that set are chosen (i.e. if hospitals “b”, “c”, and “f” are tied for best, then hospital “b” should be returned).
The function also checks the validity of its arguments. If an invalid state value is passed to best, the function throws an error via the stop function with the exact message “invalid state”. If an invalid outcome value is passed to best, the function throws an error via the stop function with the exact message “invalid outcome”.
The function rankhospital() takes three arguments: the 2-character abbreviated name of a state (state), an outcome (outcome), and the ranking of a hospital in that state for that outcome (num). The function reads the outcome-of-care-measures.csv file and returns a character vector with the name of the hospital that has the ranking specified by the num argument. For example, the call rankhospital("MD", "heart failure", 5) would return a character vector containing the name of the hospital with the 5th lowest 30-day death rate for heart failure. The num argument can take values “best”, “worst”, or an integer indicating the ranking (smaller numbers are better). If the number given by num is larger than the number of hospitals in that state, then the function would return NA. Hospitals that do not have data on a particular outcome will be excluded from the set of hospitals when deciding the rankings.
Handling ties. It may occur that multiple hospitals have the same 30-day mortality rate for a given cause of death. In those cases ties should be broken by using the hospital name.
The function also checks the validity of its arguments. If an invalid state value is passed to rankhospital, the function throws an error via the stop function with the exact message “invalid state”. If an invalid outcome value is passed to rankhospital, the function throws an error via the stop function with the exact message “invalid outcome”.
The function rankall() takes two arguments: an outcome name (outcome) and a hospital ranking (num). The function reads the outcome-of-care-measures.csv file and returns a 2-column data frame containing the hospital in each state that has the ranking specified in num. For example the function call rankall("heart attack", "best") would return a data frame containing the names of the hospitals that are the best in their respective states for 30-day heart attack death rates. The function should return a value for every state (some may be NA). The first column in the data frame is named hospital, which contains the hospital name, and the second column is named state, which contains the 2-character abbreviation for the state name. Hospitals that do not have data on a particular outcome are to be excluded from the set of hospitals when deciding the rankings.
Handling ties. The rankall function handles the ties in the 30-day mortality rates in the same way that the rankhospital function handles ties.
The function also checks the validity of its arguments. If an invalid outcome value is passed to rankall, the function throws an error via the stop function with the exact message “invalid outcome”. The num variable can take values “best”, “worst”, or an integer indicating the ranking (smaller numbers are better). If the number given by num is larger than the number of hospitals in that state, then the function will return NA.