Planning, designing, performing and publishing animal experiments Flashcards Preview

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Flashcards in Planning, designing, performing and publishing animal experiments Deck (10):
1

Good experimental design will help me to

  • improve the quality of my scientific work
  • get published in better journals
  • save time and money
  • use fewer animals

2

On which (six) variables does the power analysis depend?

  • group size
  • relevant effect of treatment (signal)
  • standard deviation (noise)
  • desired power
  • level of significance
  • alternative hypothesis

3

Types of experiments:

  • pilot study
  • exploratory experiments
  • confirmatory experiments
  • experiments to explore relationships between variables

4

Objectives of pilot studies

  • logistics - setup of experimental protocol
  • to analyse effect of treatment
  • to analyse variation (noise)
  • determine size of experiment
  • staff training

5

Objectives of exploratory experiments

  • develop hypotheses for further testing
  • measure many outcomes
  • data snoopign --> hypothesis testing
  • should be confirmed in a controlled expeirment
  • analysed in a ANOVA

6

Objectives of confirmatory experiments

  • is a comparison
  • tests a null hypothesis
  • subjects are randomised
  • should, if possible, be blind
  • need to be powerful - have high probability of detecting an effect

7

Objectives of experiments to explore relationship between variables

  • tests whether two variables are associated
  • if so, the nature of that relationship

8

Name three ways of randomisation

  • completely randomised design (computer)
  • randomised block design
  • latin square design

9

Characteristics of randomised block design

  • deals with known (suspected) heterogeneity
  • breaks up an experiment into mini experiments
  • subsets of experimental units (animals) e.g. males and females, large and small etc.

(so that you don't end up having all large or femal animals in one group)

10

What are the properties of a well-planned experiment?

  • have a clear specification of the aims of the experiment
  • is unbiased
  • is powerful
  • has a wide range of applicability
  • should be simple
  • should be possible to statistically analyse