inv_u_trend {NCC}

Generation of an inverted-u trend

Description

This function generates a time trend for given time points in the trial according to an inverted-u function.

Usage

inv_u_trend(j, lambda, N_peak, n_total)

Arguments

j

Time points for which the trend should be generated.

lambda

Strength of time trend.

N_peak

Point at which the time trend switches direction in terms of overall sample size.

n_total

Total sample size in the trial.

Details

The time trend is generated according to the function f(j) = \lambda \cdot \frac{j-1}{N-1} (I(j \leq N_p) - I(j > N_p)), where N is the total sample size (parameter n_total) and N_p (parameter N_peak) indicates the point at which the trend switches direction.

Value

Time trend for time points j.

Author(s)

Marta Bofill Roig, Pavla Krotka