Studied by 104 peopleStatistics =
Statistics = Basic Math + Context + Interpretation
Variables
Characteristics that can change or take on different values
Most research begins with a _
Most research begins with a general question about the relationship between 2 variables for a specific group
Population
An entire group of individuals
Label the 2 variables and population in the question: What’s the relationship between weekend drinking and academic performance among 1st year college students
weekend drinking is variable 1, academic performance is variable 2, 1st year college students is population
Sample
group of individuals selected to represent the population as usually populations are too large to examine the entire group
Inferential Statistics
Use sample data to make general conclusions about population
An example of inferential statistics
Presidential polling
Methods for organizing data
Tables or graphs
Methods for summarizing data
Descriptive values
Descriptive value for a population
parameter (the p’s go together)
Descriptive value for a sample
statistic (the s’s go together)
Sampling error
discrepancy between a sample statistic and its population parameter
Data
measurements obtained in research
Goal of statistics
to help researchers organize and interpret data
Discrete variables
consist of indivisible categories
Example of discrete variable
dice roll, score of football game, number of tickets sold
Continuous variable
categories that are infinitely divisible into any unit the researcher chooses
Example of continuous variable
time, weight, length
4 major scales of measurement
the scale chosen determines the types of questions that can be answered with the data: nominal, ordinal, interval, and ration
Nominal scale
an unordered set of categories identified by name only
Ordinal scale
an ordered set of categories, tells you the direction of difference between two individuals
Interval scale
an ordered series of equal sized categories, identify the direction and magnitude of a difference, zero point is located arbitrarily
Ratio scale
an interval scale where a value of zero indicates none of the variable, identify the direction and magnitude of differences
Which of the four levels of measurement categories and labels variables
Nominal, ordinal, interval, ratio
Which of the four levels of measurement ranks categories in order
Ordinal, interval, ratio
Which of the four levels of measurement has known equal intervals
Interval, ratio
Which of the four levels of measurement has a true or meaningful zero
Ratio
Goal of correlational studies
determine the strength and direction of the relationship between two variable
Correlational studies
uses observations of the two variables as they exist naturally
Correlation ________ causation
Correlation does not equal causation
Experiments
examine the relationship between 2 (or more) variables by changing one variable and observing the effects on the other variable
Independent Variable
a condition or event manipulated by experimenter (I decide)
Dependent Variable
an aspect of behavior thought to be affected by the independent variable (Depends on what I decide)
Nonexperimental studies
similar to experiments because they also compare groups of scores, do not use a manipulated variable to differentiate groups, the IV is a pre existing participant variable or a time variable
“X” or “Y” indicates
individual measurements or score obtained
“N” indicates
Number of individuals in a data set for a population
“n” indicates
Number of individuals in a data set for a sample
P in PEMDΣAS
calculations within parentheses are first
E in PEMDΣAS
exponents are second
MD in PEMDΣAS
multiplying and dividing are tied for third and must be completed from left to right
Σ in PEMDΣAS
Forth is summation with the Σ notation
AS in PEMDΣAS
Finally the remaining adding and subtracting is completed from left to right
Note
Flashcard