μ=1.0; σ=1.0; n=5;
x=RandomVariate[NormalDistribution[μ,σ],n]
c90a=0.711;
c90b=9.488;
c95a=0.484;
c95b=11.143;
c99a=0.207;
c99b=14.860;
s2=Variance[x];
s=Sqrt[s2]

x190=(n-1)*s2/c90b;
x290=(n-1)*s2/c90a;
x195=(n-1)*s2/c95b;
x295=(n-1)*s2/c95a;
x199=(n-1)*s2/c99b;
x299=(n-1)*s2/c99a;
Print["I normale 90 = ",Sqrt[x190],"   ",Sqrt[x290]]
Print["I normale 95 = ",Sqrt[x195],"   ",Sqrt[x295]]
Print["I normale 99 = ",Sqrt[x199],"   ",Sqrt[x299]]

μ=1.0; σ=1.0; n=30;
x=RandomVariate[NormalDistribution[μ,σ],n]
c90a=17.708;
c90b=42.557;
c95a=16.047;
c95b=45.722;
c99a=13.121;
c99b=52.336;
s2=Variance[x];
s=Sqrt[s2]

x190=(n-1)*s2/c90b;
x290=(n-1)*s2/c90a;
x195=(n-1)*s2/c95b;
x295=(n-1)*s2/c95a;
x199=(n-1)*s2/c99b;
x299=(n-1)*s2/c99a;
Print["I normale 90 = ",Sqrt[x190],"   ",Sqrt[x290]]
Print["I normale 95 = ",Sqrt[x195],"   ",Sqrt[x295]]
Print["I normale 99 = ",Sqrt[x199],"   ",Sqrt[x299]]

μ=1.0; σ=0.2; n=5;
x=RandomVariate[NormalDistribution[μ,σ],n];
c90a=0.711;
c90b=9.488;
c95a=0.484;
c95b=11.143;
c99a=0.207;
c99b=14.860;
s2=Variance[x];
s=Sqrt[s2]

x190=(n-1)*s2/c90b;
x290=(n-1)*s2/c90a;
x195=(n-1)*s2/c95b;
x295=(n-1)*s2/c95a;
x199=(n-1)*s2/c99b;
x299=(n-1)*s2/c99a;
Print["I normale 90 = ",Sqrt[x190],"   ",Sqrt[x290]]
Print["I normale 95 = ",Sqrt[x195],"   ",Sqrt[x295]]
Print["I normale 99 = ",Sqrt[x199],"   ",Sqrt[x299]]

μ=1.0; σ=0.2; n=30;
x=RandomVariate[NormalDistribution[μ,σ],n];
c90a=17.708;
c90b=42.557;
c95a=16.047;
c95b=45.722;
c99a=13.121;
c99b=52.336;
s2=Variance[x];
s=Sqrt[s2]

x190=(n-1)*s2/c90b;
x290=(n-1)*s2/c90a;
x195=(n-1)*s2/c95b;
x295=(n-1)*s2/c95a;
x199=(n-1)*s2/c99b;
x299=(n-1)*s2/c99a;
Print["I normale 90 = ",Sqrt[x190],"   ",Sqrt[x290]]
Print["I normale 95 = ",Sqrt[x195],"   ",Sqrt[x295]]
Print["I normale 99 = ",Sqrt[x199],"   ",Sqrt[x299]]

(* Ross Cap. 7 n. 40 *)

x={50.6,54.8,54.4,44.9, 42.1,69.8,53.6,66.1,48.0,37.8}
n=Length[x]

s2=Variance[x];
s=Sqrt[s2]

c90a=3.325;
c90b=16.919;
c95a=2.7;
c95b=19.023;
c99a=1.735;
c99b=23.589;

x190=(n-1)*s2/c90b;
x290=(n-1)*s2/c90a;
x195=(n-1)*s2/c95b;
x295=(n-1)*s2/c95a;
x199=(n-1)*s2/c99b;
x299=(n-1)*s2/c99a;

Print["I normale 90 = ",Sqrt[x190],"   ",Sqrt[x290]]
Print["I normale 95 = ",Sqrt[x195],"   ",Sqrt[x295]]
Print["I normale 99 = ",Sqrt[x199],"   ",Sqrt[x299]]