Research Methods Flashcards
What is a hypothesis?
An educated guess as to what will happen during an experiment
What is a null hypothesis?
A hypothesis that states there will be no change during an experiment (no statistical relationship)
What is random sampling?
A subsample is chosen randomly from a larger set (e.g. random number generator)
What is the importance of random sampling?
Avoids bias
What is systematic sampling?
A subsample is chosen from a larger set with a fixed periodic interval (e.g access points along a river)
What is the importance of systematic sampling?
Regular sample intervals
What are the 2 types of transect?
- Line transect
- Belt transect
Where are transects applied?
To environmental gradients
Why is sample timing important?
To ensure variability is detected
What is sample size dependent on?
Homogeneity
What is sample number dependent on?
Variability
Why is standardisation important?
To allow comparisons between different experiments and ensure consistent reliability
What are the 3 types of quadrat?
- Frame
- Grid
- Point
What do the 3 types of quadrat measure?
- Frame - percentage frequency
- Grid - percentage cover
- Point - local frequency
What are the limitations of quadrats?
- Subjective observations
- Plants may be flattened
What are kick sampling and surber sampling used for?
Sampling of freshwater invertebrate species
How does kick sampling work?
- Net held downstream in a river
- Agitation through kicking
- Invertebrates are caught in the net
What are the limitations of kick sampling?
- Organisms may swim away
- Difficult to standardise
How does surber sampling work?
- Net attached to a frame is held downstream in a river
- Agitation in the frame using a trowel or a stick
- Invertebrates are caught in the net