Question

Determine the experimental design (1 mark)

Below, the aim of the study is stated, along with the data collected to answer the aim. Select the option that best describes this experimental design. Assume that the only tests of interest are stated in the aim. Assume that the data are analysed without any aggregation (e.g. taking averages) unless stated otherwise.

Aim: To test how the difference between the call frequency of coastal vs. inland bird species differs in summer vs. winter.

Data: Ten individuals from each of five species of coastal birds and five species of inland birds (100 individuals total) has their call frequency measured twice (once in summer, once in winter). The call frequency on each measurement date is put into the analysis, and the researchers test whether the change in frequency between seasons differs for the coastal vs. inland species.

Select one:

a. Randomised block

b. Split-plot

c. Replicated block

d. Nested

e. Completely randomised

Aim: To test for differences in the call frequency of coastal vs. inland birds of a single species.

Data: Ten islands were selected for the study. On each island, a bird was selected at a coastal site and another at an inland site. For each bird, the call frequency (number of calls during the study period) was measured and put into the analysis.

Select one:

a. Randomised block

b. Completely randomised

c. Nested

d. Split-plot

e. Replicated block

Answer 1

What is Experimental Design?

The analysis of data generated from an experiment. It is wise to take time and effort to organize the experiment properly to ensure that the right type of data, and enough of it, is available to answer the questions of interest as clearly and efficiently as possible.

BIrd Calls:

the bird calls are communication signals that transfers useful info from one individual to other of the same species.

Aim1:

To test how the difference between the call frequency of coastal vs. inland bird species differs in summer vs. winter?

We have taken 5 coastal species and 5 inland species.

From Each species call frequency of 10 birds is recorded.

call frequencies are recorded in summer and winter.

1) Randomised Block :

The principle of randomization involves the allocation of treatment to experimental units at random to avoid any bias in the experiment resulting from the influence of some extraneous unknown factor that may affect the experiment.

In the development of analysis of variance, we assume that the errors are random and independent. In turn, the observations also become random. The principle of randomization ensures this. T

a) It eliminates the systematic bias.

b) It is needed to obtain a representative sample from the population.

c) It helps in distributing the unknown variation due to confounded variables throughout the experiment and breaks the confounding influence.

If the randomization process is such that every experimental unit has an equal chance of receiving each treatment, it is called a complete randomization.

We have two types of bird species:

1) Coastal

2) Inland

Two tables layouts will be generated and for each species with two rows, one will be for summer and other will be for winter, The layout will have 10 columns representing each bird .

call frequency of one specie can be assigned to 10 birds randomly.

Randomization:

Number the species

Number the birds

Randomly allocate the call frequency of each species to the corresponding group of 10 birds.

Compare the results between two rows of season Summer and Winter

Aim2:

To test for differences in the call frequency of coastal vs. inland birds of a single species.

We have taken 1 coastal specie and 1 inland specie.

From Each specie call frequency of 10 birds is recorded.

Split plot:

Two splits are created for each species.

each split have 10 columns

call frequency of 10 individual birds can be assigned randomly.

Randomization:

Number the birds for each species

Randomly allocate the call frequency of each bird to the splitted columns.