Generation of a linear trend that starts in a given period

This function generates a time trend for given time points in the trial according to a linear function.

Usage

linear_trend(j, lambda, sample_size, trend_mean, trend_var)

j: Time points for which the trend should be generated.
lambda: Strength of time trend.
sample_size: Vector of dimension 2, indicating sample size in the trial period until the time trend starts and the remaining sample size.
trend_mean: Integer. In case of random time trends, the strength of the time trend will be generated from N(trend_mean, trend_var).
trend_var: Integer. In case of random time trends, the strength of the time trend will be generated from N(trend_mean, trend_var).

Time trend for time points j.

The time trend is generated according to the function \(f(j) = \lambda \cdot \frac{j-1}{N-1}\), where \(N\) is the total sample size.

Marta Bofill Roig, Pavla Krotka