Lesson 1: Intro to Statistics Flashcards
What are statistics?
Set of mathematical procedures for organizing, summarizing, and interpreting information
What is a population?
The entire group of individuals
- ex: PSYC204 students
What is a sample?
A smaller group selected from the population
- ex: students that participate to the polling in class
What is a variable?
A characteristic or condition that can change or take on different values
What is data?
The measurements obtained in a research study
- ex: answers during the first polling in class (excited, nervous, hungry, etc.)
What are descriptive statistics?
Methods for organizing and summarizing data
- ex: tables, graphs, averages
What is a descriptive value for a population? For a sample?
Population: parameter
Sample: statistic
What are inferential statistics?
Methods for using sample data to make general conclusions (inferences) about populations
- “margin of error,” “statistically significant”
What is sampling error?
Discrepancy between a sample statistic and its population parameter
- you want to minimize the sampling error, but it’s hard to, since you can’t ever get the whole population parameter (you only get statistics, which are from samples)
What are the two main types of variables?
- Discrete variables: consist of indivisible categories, each unit being the smallest it can be
- fruit, political party, etc. - Continuous variables: infinitely divisible into whatever units a researcher may choose
- ex: time, weight, height, etc.
What are real limits?
Boundaries of each interval representing scores measured on a continuous number line
- upper real limit marks the top of the interval
- lower real limit marks the bottom of the interval
What is a nominal scale?
An unordered set of categories identified only by name
- ex: fruit categories
What is an ordinal scale?
An ordered set of categories. Can tell you the direction of difference between two individuals
- ex: small, medium, large
What is an interval scale?
An ordered series of equal-sized categories. Can identify the direction and magnitude of a difference.
- zero value does NOT mean none of the quantity
- ex: temperature
What is a ratio scale?
Interval scale where a value of zero indicates NONE of the variable. Can identify the direction and magnitude of differences and allow ratio comparisons of measurements
- ex: time, weight, height, etc.
What is an experiment?
One variable is manipulated to create treatment conditions. A second variable is observed and measured to obtain scores for a group of individuals in each of the treatment conditions
- demonstrates cause and effect relationships
What is the independent variable? The dependent variable?
Independent variable is the manipulated variable. Dependent variable is the observed variable
What is the best way to study the effectiveness of a treatment?
Randomized control trial
- two instances are observed and then compared to determine the effectiveness of each treatment
What are non-experimental or quasi-experimental studies?
These studies to NOT use a manipulated variable to differentiate the groups
- the variable that DOES differentiate the groups is usually a pre-existing participant variable, like male/female or before/after
