Logic, Reason & Central Tendancy Flashcards
Contrast r (pop growth) and R2 in a statistical analysis context
R is the intrinsic rate of growth of a pop, the max rate of growth possible under perfect conditions
R2 is a measure of the amount of variation explained by the relationship of two variables
Two pop of birds. Sample mean for both is 100. Sd of urban pop 5 and 3.2 for forest pop. Which is a more precise estimate. What is sampling variance for urban
The more precise is the forest pop
Variance 25
What are the golden rules for data quality’s
Samples must be independent (every point equal chance being selected) and random (data selected at random)
Three types of variables
Categorical: heavy, intermediate, light (put into categories)
Continuous data: that can take the form of a decimal (weight, height)
Discrete data: can’t take form of decimals (students, trees)
After a data set is ranked, the value in the middle of the distribution is called the ________
Median
The mode of a distribution is defined __________
The most common value (occurring most often)
If the variation within a data set is high, the number of samples required in order to draw confident conclusion increases or decreases. Explain
When variation is high, the average distance between any one point and the mean is high and therefore means more samples are needed to describe the distribution. If there is no variation at all, only one data point would be necessary to describe the distribution of values (because each sample would be identical)
As the sample size increases does the margin of error increase or decrease
Decreases because as you increase the sample size it can increase the randomness and allow for less error to form
Common sense
Basic ability to perceive, understand, and judge things, common to nearly all people and without need for debate
Evidence
Factual knowledge or data the supports or casts doubt on the hypothesis
Empirical evidence
Is a collective term for the knowledge or source of knowledge acquired by means of the senses, particularly by observation and experimentation
How is knowledge gained by observation a challenge
We lack the quality control feedback loops to evaluate the quality of its products
We see patterns everywhere and are prone to invent casual relationships in their explanation
What happens when perception is not questioned
Patterns are changed and concepts are invented with willful ignorance of ambiguity
Variable
Any defined characteristic that varies from one biological entity to another
Plant height, bird weight
Samples are selected randomly from a pop
Population (statistical)
The entire collection of entities we are interested in
Lice load on salmon, pop distribution and abundance
Sample
Subset of the pop being measured and used to estimate the distribution of the variable within the true pop
Parameter
Any calculated measure used to describe or characterize a pop
Pop mean is the single, fixed value parameter
Statistic
An estimate of the pop parameter
Sources of variation
Naturally occurring and sampling var
Your research must capture and quantify both
Descriptive statistics
Central tendency: mean, median, mode
Variation: amount of variation explained by the best fit line (min ave distance of each data point to the line) between two variables
Why use statistics
Can almost never know the entire pop of interest
Allows us the estimate these values for entire pop based on samples
Can allow us to calculate the level of confidence in our results (larger # samples the greater the prob statistic accurately reflects the parameter)
