Pilot Study's and Experimental Variables Flashcards
What is a pilot study?
A short experiment carried out before a scientific investigation to develop and improve experimental protocols. It provides data to ensure the validity of the design, the effectiveness of techinques, determines a suitable range for the independent variable, identifies confounding variables and identifies a suitable number of replicates.
How do you ensure an experiment has high validity?
- Ensure there are sufficient control groups.
- Enusuring the variables are controlled tightly.
What is a confounding variable?
A variable other than the independent variable that has an effect on the dependent variable. If it can’t be controlled a randomised block design may be used.
How can a reliable conclusion be made?
By ensuring the experiments have a suitable number of replicates.
What is a simple and a multifactorial experiment?
A simple experiment is one where only one independent variable is changed (most lab studies).
A multifactorial experiment is when more than one indepenedent variables are changed (most field studies).
What are advantages and disadvantages of single and multifactorial experiments?
Simple: Advantages include it is a simpler design, variables can be tightly controlled and results are easy to analyse. Disadvatages include it is difficult to generalise the results to whole organsims and it isn’t suitable for testing a complex hypotheses.
Mulitfactorial: Advantages include it allows the examination of complex intercations, and allows generalisations to be made. Disadvantages include it is more complex and time-consuming, its difficult to control variables and results are harder to analyse.
What is discrete and continous data?
Discrete - have finite values that allow them to be put into groups e.g. sex, number of pets etc.
Continuos - changes gradually from one extreme to another e.g. height, age, concentration.
Whats qualitative, quantitative and ranked data?
Qualitative - descriptive, difficult to analyse e.g colour of leaf.
Quantitative - Measured directly and recorded as numbers so easier to analyse e.g. concentration, time etc.
Ranked - data is put into order of magnitude. e.g. abundance of plant.
