Parametric test oo is unknown and has to be estimated from the data: a2=∑1=(xai-x,)2+∑1(xb1-xb2 m+n-2 For the mouse data ASL =.131 the null hypothesis cannot be rejected. o However,this(parametric)method relies on the hypotheses made while calculating the ASL. R.Dahyot (TCD) 453 Modern statistical methods 2005 10/22Parametric test σ is unknown and has to be estimated from the data: σ 2 = Pn i=1(xai − xa) 2 + Pm i=1(xbi − xb) 2 m + n − 2 For the mouse data ASL = .131 : the null hypothesis cannot be rejected. However, this (parametric) method relies on the hypotheses made while calculating the ASL. R. Dahyot (TCD) 453 Modern statistical methods 2005 10 / 22