week one Flashcards
What is a hypothesis?
general explanation for a particular pattern
“explanation on trial”
What are the three general rules for writing a hypothesis?
1) must be generalized
2) don’t write increases/decreases, write affects
3) avoid the word “will”
What is a prediction?
predicted outcome of your particular study
Q: How has the widespread planting of non-native trees species affected the abundance and diversity of butterflies? Write a hypothesis and prediction.
some options include of hypothesizes:
1) lack of native street trees affects the abundance and diversity of butterflies
some options for predictions:
1) we predict higher caterpillar diversity in native trees compared to non-native trees
2) more non-native tress will cause a decrease in amount of caterpillars and diversity
What are the three experimental environment methods?
Lab, Field and Observational
What are the two benefits of Lab experiments?
What is the drawback to lab experiments?
1)highly controlled, easy to replicate
2)limited application to the “real world”
What is the benefit to Field experiments? What is the drawback of Field experiments?
1) more realistic than lab
2) random variation among replicates produces “noisy” data
How do you overcome noisy data?
strength of treatment needs to be stronger than random environmental variation
eg. concentration of salt in water (lots of salt needs to be added)
What is the benefit to observational studies? What are the three drawbacks?
1) “real world” patterns
2.a) potentially a lot of variables
b) hard to determine exact measurements of variables
c) statistically very intensive
What can assist observational studies to data collection easier?
biodiversity databases
What are the benefits and drawbacks of biodiversity databases?
- enormous amount of data
- a) quality of data is unknown ( don’t know collection methods)
b)data is not collected using consistent methods
What is replication and why is it important?
repeating experiments to ensure same results for integrity of study
What does amount of replication needed depend on? When is it needed less? When is it needed more?
1) depends on strength of effect you are expecting relative to how much unmeasured variation there is in a study
2) very strong effect=minimal replication needed
3) very weak effect=lots of replication needed
Which experimental environment method is the most effective when conducting a study?
A combination of all three. Lab, Field and Observational
