(* Ross Cap. 7 n. 44 *)

Clear[x,y]

x={3250.,3268, 4302, 3184, 3266, 3297, 3332, 3502,3064, 3116};
y={3094., 3106, 3004, 3066, 2984, 3124, 3316, 3212, 3380, 3018};
n=Length[x]
m=Length[y]

t90=1.833;
t95=2.262;
t99=3.250;

mx=Mean[x]
my=Mean[y]
s2x=Variance[x];
s2y=Variance[y];
s2p=((n-1)*s2x+(m-1)*s2y)/(n+m-2);
sp=Sqrt[s2p]

d190=mx-my-t90*sp*Sqrt[1/n+1/m]
d290=mx-my+t90*sp*Sqrt[1/n+1/m]
d195=mx-my-t95*sp*Sqrt[1/n+1/m]
d295=mx-my+t95*sp*Sqrt[1/n+1/m]
d199=mx-my-t99*sp*Sqrt[1/n+1/m]
d299=mx-my+t99*sp*Sqrt[1/n+1/m]