Example
3.3
Four groups of soya bean plants that are exposed to different treatments.
The response is the total area of the leaves. The treatments are the
combinations of two levels of stress and two levels of light. The
data are used to illustrate the two-way analysis of variance. In this
example each cell has several observations, and therefore the reduction
to the additivity model may be tested. |
Example
3.4
The recordings of systolic blood pressure and age for two professions
are used to illustrate the comparison of regression lines. |
Example
4.6
The data are from
six drillings in an area. Each drilling results in a core of soil,
and the response being considered is the pH-value of the soil at the
top, in the middle, and at the bottom of the core.
In this example each cell one observation only, and therefore the
reduction to the additivity model can only be tested graphically.
|
Exercise
4.1
The purpose of the experiment considered in this exercise was to study
how the amount of chromium in fertilized eggs of salmon, Salmon
trutta L depends on the exposure to chromium.
In this exercise the statistical technique is two-way analysis of
variance. |
Exercise
4.2
The same data as in Exercise 4.2, but in this exercise the
statistical technique is comparison of regression lines. |
Exercise
4.3
This exercise considers data from an experiment that was made to describe
the connection between the effective diffusion, D, of a core of sand
as a function of the degree of cementation, C, of the sand. The effective
diffusion describes how easily gasses diffuse through the core of
sand and the degree of cementation is a number between 0
and 1, describing the reduction of the initial volume of the cavity
between the grains of sand.
The statistical technique is comparison of regression lines. |
Exercise
4.4
The velocity of evaporation of water from the surface of the skin
(transepidermic water loss, TEWL) may be used as an indirect measure
of the permeability and the barrier function of the skin. Data has
been obtained from workers in the fishing industry and from workers
forming a control group.
The statistical technique is comparison of regression lines. |
Exercise
4.5
24-hour average of the contents of lead in the air recorded by two
measurements stations in Aalborg in between 1983 and 1989.
The statistical technique is comparison of regression lines. |
Exercise
4.6
The data for this exercise are from a study of the sand lizard
Lacerta agilis.
Eggs from the sand lizard were placed in incubators under carefully
controlled conditions and a range of variables were recorded for the
hatchlings, including the incubation time, which is the variable studied
in this exercise.
The data in this exercise was used in Example 1.2.
The exercise offers an opportunity to use two-way analysis of variance
as well as regression methods. |
Exercise
4.7
The data in this exercise are from an experiment on the effect
of compounds of nitrate and phosphate used as fertilizers on potatoes.
The exercise offers an opportunity to use two-way analysis of variance
as well as regression analysis. |
Exercise
4.8
In order to make 100 concrete flagstones, a manufacturer adds 10 kg
of an additive A in order to reduce the curing time. The manufacturer
has become aware of an additive B which is cheaper than A and is supposed
to have the same effect. In order to investigate whether B or a mixture
of A and B can possibly replace A in the production, an experiment
is performed, and the data
are considered in this exercise.
The exercise offers an opportunity to use two-way analysis of variance
as well as regression analysis. |
