Exam 1 Flashcards
(168 cards)
Sampling issues: sample size
May be difficult to get enough sample size to make good/reliable decisions
Sampling issues: spatial heterogeneity
Most populations are not evenly distributed
Sampling issues: temporal heterogeneity
Populations change over time
Sampling issues: sampling variability
Two random samples of the same population might yield slightly different results
The number of times a treatment is repeated
Replication
The standard of comparison (no treatments applied)
Controls
Every individual or sample unit has equal chance of being sampled from the population
Ensure samples are not biased
Protects against unrecognized influences
Randomization
Types of data: nominal or discrete or categorical
Age, status
Types of data: ordinal or rank
Abundance, wind speed
Types of data: continuous
Body mass, rainfall
Basic sampling designs: every sample unit/animal in the population has equal chance of inclusion
One of the most commonly used
Ensure randomly selected
Simple random
Simple random with replacement probably best used when you have ____ samples to work with
Smaller
Basic sampling designs: subpopulations identifies and sampled
Use when you potentially have differences in densities
Stratified random
Basic sampling designs: units/animals sampled at regular intervals
Randomly selected starting points
Simple systematic
Basic sampling designs: form of other sampling methods, but units are clustered for sampling due to similarity in habits or clusters of animals
Cluster sampling
Basic sampling designs: similar to cluster sampling, but you don’t cluster before sampling, cluster after finding animal or plant
Adaptive sampling
Adaptive sampling is primarily used for ____/___________ animals
Rare/uncommon
Null is true—> reject null
Type 1 error
Null is true —-> do not reject null
Correct decision
Null is false —> reject null
Correct decision
Null is false —> do not reject null
Type 2 error
Which type of error is worse?
Type 1 —> created false new knowledge
The ability to reject the null when you should
Power
How do you get more power?
- Increase sample size —> best way
- Change alpha
- Effect size