in which q is normalized to q$_{0}$ = 1 /τ . The normalized correlation function both in the non– improved and improved cases are plotted in figure (1). Figure 1: The normalized non–improved (solid line) and improved (dotted line) correlation function versus the normalized wave number (q), with ϵ = 0 . 3. One can see in this plot that the effect of improvement coming from the running couplings is to have a little larger correlation for large wave numbers. The relative correction of the correlation function is shown in figure (2) for three different values of the slow roll parameter. It shows that the correction becomes smaller as the slow roll parameter decreases. This correction is about (for q = q$_{0}$ ) 5 % for ϵ = 0 . 300, 5 × 10 − 2 % for ϵ = 0 . 030 and 5 × 10 − 4 % for ϵ = 0 . 003. 20