Question

experimental design scenarios. state the hypothesis being tested and critique the experimental design

(a) Some plants produce chemicals that are thought to repel insect herbivores. The plant Arabidopsis
thaliana, a small fast growing brassica, is a model organism used extensively in plant genetic research.
There are many different ecotypes, or strains. A new wild population has been found with plants
growing on sandy soil suffering greater rates of herbivory from a weevil (a type of beetle) species than
those growing 500 metres away by road-side verges.
How might you use a field study/experiment to investigate the relative influence of plant genetics
(controlling plant chemicals) and the environment (soil type, weevil abundance etc.) on the amount of
herbivory? First state a testable hypothesis(es).

(b)Ants are known to have mutualisms with plant sap-sucking bugs. The ants obtain honeydew, a sugary
liquid which the bugs extrude, in exchange, it is thought, for protecting bugs from predators (e.g. birds,
other insects) and parasites (commonly wasps that lay eggs in the bug, with the larvae growing inside
and eventually killing the bug). Horticulturists believe that the ant-bug mutualism results in even more
negative effects on plant growth than when only bugs are present on the plant.
Describe a laboratory study/experiment to examine the relationship between plant growth and
presence/absence of bugs and ants. You have access to three controlled growing areas and
funds for 100 plants.

(c)Students that regularly attend lectures are known to do better in exams than those that do not. Dr
Brown thinks that this is because students who regularly attend lectures are more likely to form study
groups. Design an experiment to investigate this idea.

Answer 1

a)

H0 : plants growing on sandy soil suffering greater rates of herbivory from a weevil species than those growing 500 mitres away by road side verges.

H1 : plants growing on sandy soil doesn't suffering greater rates of herbivory from a weevil species than those growing 500 mitres away by road side verges.

b)

here we can use 2 way ANOVA of which would describe by the plant growth and absent of bugs & ants as treatments and three controlled growing areas and funds of 100 plants as the block for the above type of problem.

c)

Test would be conduct by the study of a chi square test as the number of students are to be designed in a huge manner. So we can perform a chi-square test to justify the null hypothesis is acceptable or not.