Bio Quiz

Mean

The total of the numbers divided by how many numbers there are; the average

The most frequently used measure of central tendency if there are no major outliers

Mode

The number that appears the most

the preferred measure when data are nominal (separate categories, ex. Eye color of students)

Median

The number which is in the middle of the middle value

1. the preferred measures when:

   1. There are a few extreme scores (a single outlier can have a great effect on the mean). 

   2. There are some missing or undetermined values in your data. 

   3. The data is ordinal (categories that go in order, ex. Happiness on a scale of 1-5).

Range

The difference between the largest and the smallest number

Does not measure central tendency, but rather how well the central tendency represents the data. 

Simpson’s Diversity Index (SDI)

a measure of diversity which takes into account the number of species present (species richness), as well as the relative abundance of each species (species evenness)

SDI Equation

SDI = 1 - ∑ (n/N²)

n= total number of a particular species

N= total number of organisms of all species

∑= the sum of

Species

a group of living organisms consisting of similar individuals capable of exchanging genes/ interbreeding

Biodiversity

refers to the variety of living species on Earth, including plants, animals, bacteria, and fungi

Species Richness

the number of species within a defined region

Species Evenness

the number of organisms in each species within a defined region

Scatter Plot

• Dependent variable IS continuous

• Points are plotted using x- and y-components

• The points are NOT connected because the observations are independent (the next value does NOT depend on the previous value)

• Uses a best-fit line or curve to show relationship

Bar Graph

• Dependent variable is NOT continuous

• There is no order to the categories on the X-axis

• Bars typically don’t touch

• Y-axis is usually a percentage or a frequency (count)

Histogram

• A specific type of bar graph

• Dependent variable must have a natural order that can be grouped into defined “chunks”

• Bars must always touch

• Y-axis is usually a percentage or a frequency (count)

Pie Chart

• Dependent variable is NOT continuous

• Usually presents data as a “part of a whole” or as percentages

Line Graph

• Dependent variable IS continuous

• Points are plotted using x- and y-components

• The points are connected because the observations are NOT independent (the next value depends on the previous value)

Extrapolate

To guess or think about what might happen using information that is already known

Population Sampling

the process of taking a subset of subjects that is representative of the entire population

Direct Census

A method for estimating population size for small and stationary populations (the most accurate)

Mark-Release-Recapture

A method for estimating population size of larger, motile species

Quadrat Sample

A method for estimating population size for larger, stationary populations

Quadrat Plotting

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