Statistics 1 Flashcards
Population
Everyone/everything we are getting a sample from.
Sample
A subset of the population.
Census
Testing an entire population. Not sampling.
Descriptive Statistics
The process of summarizing and presenting the sample data in a condensed form.
Inferential Statistics
The process of generalizing from our sample data to draw conclusions about our population.
Numerical Data
Data in the form of numbers (ex. time, distance, amount).
Categorical Data
Data in the form of categories (ex. type, yes or no).
Continuous
Numerical data that can take on an entire range of values (ex. time, lengths).
Discrete
Numerical data that has a restricted amount of values (ex. dollars).
Univariate
A single set of numerical data.
Bivariate
A paired set of numerical data.
Bar Graphs
Display for categorical data.
Frequency (Bar Graphs)
Displaying the number of __.
Relative Frequency (Bar Graphs)
Displaying the % of a category. Demonstrating proportions.
Dot Plots
Number lines with small dots above data values.
Observational Study
Study where the investigator collects data. The easiest and most common way to collect data.
What can you draw from an observational study?
You can draw conclusions about a single population or compare two populations.
Experiment
Where the investigator actively manipulates the subjects.
Experimental Units
Subjects being tested.
What can you draw from an experiment?
You can draw a “cause and effect” relationship.
Random Selection
Selecting a sample from your population at random.
Random Assignment
Randomly selecting people from your sample and putting them into different treatment groups.
Simple Random Sampling
Get all names from population and choose your sample in a random way from the list (ex. put in hat, shake, pick).
Stratified Random Sampling
If population is naturally split into subgroups and you want to represent each group proportionately, sample each group separately.