Biomedical Engineering Reference
In-Depth Information
and
n
i
x
Ai
=
=
1
m
A
n
A
in addition to
n
i
x
Bi
=
1
=
m
B
n
B
x
Ai
and x
Bi
:dataofgroupAandB,respectively;m
A
and m
B
: mean
of the respective values; n
A
and n
B
:numberofdataoftherespective
groups; F: degree of freedom
Prerequisite for the
t
-test is a normal distribution of data, i.e.,
the frequencies of data with the same deviation from mean forms
a bell-shaped curve. In case of a large number of experimentally
obtained data, mostly a Gaussian distribution is given.
In practice, P is given as a threshold for statistical significance
and a low P is read as more significant than a higher value. In
a strong sense, this definition is not correct, but this interpretation
is common usage. Table 9.2 gives P values and their explanation as
found very often in scientific literature.
References
Armitage P, Berry G, Matthews JNS (2002) Statistical methods in medical
research, 4th ed. Blackwell, Malden Massachusetts
Dawson BD, Trapp RG (2000) Basic and clinical biostatistics. Appleton and
Lange
Motulsky H (1995) Intuitive biostatistics. Oxford University Press, Oxford
Wardlaw AC (1987) Practical statistics for experimental biologists. Wiley,
Chicheser
Table 9.2.
Steps of significance
P value
Verbal expression
Symbol
<
0.001
Extremely significant
***
0.001 - 0.01
Very significant
**
0.01 - 0.05
Significant
*
>
0.05
Not significant
n.s.
9.2 Data Analysis
9.2.1 Receptor-Ligand Binding
Computation of data obtained by enzyme kinetic experiments, or
receptor binding studies using sophisticated software, are state of
