EVPI_DECREASE           A Reference Class to represent the EVPI
INMB                    A Reference Class to represent the INMB
                        (Incremental Net Monetary Benefit)
INMB_DIRECT             A Reference Class to represent the INMB
                        (Incremental Net Monetary Benefit)
Lambda                  A Reference Class to represent the lambda value
POP                     A Reference Class to represent the target
                        population
VAR_INMB                A Reference Class to represent the Hypothetical
                        variance of the Incremental Net Monetary
                        Benefit
VAR_INMB_DIFF           A Reference Class to represent the variance of
                        the Incremental Net Monetary Benefit (INMB)
                        when the standard deviation of costs and
                        effectiveness in each group differ.
VAR_INMB_DIRECT         A Reference Class to represent the theoretical
                        standard deviation of the expected INB
create_object_evpi_decrease
                        Create an object evpi_decrease
create_object_inmb      Create an object INMB
create_object_inmb_direct
                        Create an object INMB_DIRECT
create_object_lambda    Create an object lambda
create_object_pop       Create an object POP
create_object_var_inmb
                        Create an object var_inmb
create_object_var_inmb_diff
                        Create an object var_inmb_diff
create_object_var_inmb_direct
                        Create an object var_inmb_direct
gamma_risk              Function to estimate the gamma risk
graph_gain_n            Explain the estimated sample size calculated
sample_size             Function to calculate the estimated sample size
                        based on the Expected Value of Perfect
                        Information (EVPI)
