Geoscience Reference
In-Depth Information
s1 = std(corg1)
s2 = std(corg2)
which yields
s1 =
1.2550
s2 =
1.2097
h e
F
distribution has two parameters,
df1
and
df2
, which represent the
number of observations in each of the distributions reduced by one, where
df1 = length(corg1) - 1
df2 = length(corg2) - 1
which yields
df1 =
59
df2 =
59
Next we sort the standard deviations by their absolute values,
if s1 > s2
slarger = s1
ssmaller = s2
else
slarger = s2
ssmaller = s1
end
and get
slarger =
1.2550
ssmaller =
1.2097
We now compare the calculated
F
value with the critical
F
value. h is can be
accomplished using the function
finv
at a signii cance level of 0.05 (or 5%).
h e function
finv
returns the inverse of the
F
distribution function with
df1
and
df2
degrees of freedom, at the 5% signii cance level. h is is a two-tailed
test and we must therefore divide the
p
-value of 0.05 by two. Typing
Fcalc = slarger^2 / ssmaller^2
Fcrit = finv(1-0.05/2,df1,df2)