Unit 2 AICE Environmental Management

independent variable

the variable that is deliberately changed in an experiment. (the cause)

dependent variable

the variable that is measured; what changes as a result of the independent variable manipulation in experiments (the effect)

null hypothesis

A prediction that there is no difference between groups or conditions, or a statement or an idea that can be falsified, or proved wrong.

Constants

The factors that are kept the same in an experiment.

Theory

well-tested explanation that unifies a broad range of observations

reliable source

a dependable source that provides accurate and well researched information

bias

A particular preference or point of view that is personal, rather than scientific.

random sampling

a sample that fairly represents a population because each member has an equal chance of inclusion

How to reduce bias?

use random sampling

Open frame quadrat

used to measure the density per metre squared of organisms such as mussels or dandelions

Quadrat sampling

square or rectangular plot of land, a quadrat, marked off at random to isolate a sample and determine the percentage of vegetation and animals occurring within the marked area.

pitfall traps

A hole dug to catch some species for sampling.

sweep nets

A method of sampling populations of flying insects and invertebrates among vegetation.

beating trays

used to investigate insects found in vegetation. Advantages: You can take large samples, giving good estimated of the abundance of each species. Disadvantages: The sample may not be random as it will mostly be made up of insects that fall easily.

kick sampling

Used to study river organism, sediment is kicked up and a net downstream catches any organisms for a set period of time

light traps

A method of sampling populations of night-flying organisms that are attracted to lights, especially moths.

capture-mark-recapture

technique for measuring a population by capturing, marking and recapturing individuals

Lincoln index

a method for determining population size by marking and recapturing portions of a population

What does lincoln index measure?

estimated population size

Simpson's Diversity Index

a calculation for biodiversity

Geospatial Systems data collection

enables us to acquire data that is referenced to the earth and use it for analysis, modeling, simulations, and visualization.

radio tracking data collection

Using radio transmitters attached to animals to follow their movements and activity

computer modeling data collection

Using a computer and software to create a representation of an object or concept.- Climate Change

crowd sourcing data collection

allows researchers to cheaply outsource simple tasks or questionnaires, gather data in real time, and obtain far more numerous and widespread observations than in traditional data collection given its relatively low cost

Big Data

a broad term for datasets so large or complex that traditional data processing applications are inadequate.

Limitations of Big Data

amount and type of data stored; speed at which new data is generated; trustworthiness of the data; ways the data can be used

Historical Data Advantages and Disadvantages

Advantages: provides data related to performance and practices; Disadvantages: data may be inaccurate, incomplete, or not fully reflective of performance

open-ended questions

questions that allow respondents to answer however they want

close end questions

Questions designed to limit the customer's responses to one or two words.

discrete data

Numerical data values that can be COUNTED

continuous data

Numerical data values that can be MEASURED

Capture-mark-recapture

an ecological surveying technique used to measure animal populations, in which individual animals are captured, marked and released; after a time, the population is re-sampled and the number of marked animals caught gives an indication of population size.

Measuring turbidity

The Secchi disk is lowered into the water until it is no longer visible, and that depth is measured.

Transects

Used to study distribution of organisms along a line; Mark out a line in the area you want to study using a tape measure; Then collect data along this line, either by counting organisms that touch the line or by placing quadrats along the line at regular intervals

systematic sampling

select some starting point and then select every kth element in the population

random sampling advantages

simplicity and lack of bias.

Systematic sampling advantages

Simple and quick to use; Suitable for large samples and populations

species richness

the number of different species in a community

species evenness

relative abundance of each species

questionnaire

a written set of questions to be answered by a research participant

Closed-ended (fixed-choice) question

a survey question that provides preformatted response choices for the respondent to circle or check

open-ended questions

questions a person is to answer in his or her own words

How to write questionnaires

clear, simple words; Start with closed ended; write structured sentences/questions; open with a statement of purpose; guarantee it will be anonymous; limit to a maximum of 25 questions; use categories for personal info (example: age); give range of possible answers; use yes/no questions only to screen

control group

the group that does not receive the experimental treatment.

experimental group

the group in an experiment that receives the variable being tested

cluster sampling

A probability sampling technique in which clusters of participants within the population of interest are selected at random, followed by data collection from all individuals in each cluster.

stratified sampling

A type of probability sampling in which the population is divided into groups with a common attribute and a random sample is chosen within each group