Chapter 1 Flashcards
Statistics
Refers to a set of mathematical procedures for organizing, summarizing and interpreting information
Sample
Set of individuals selected from a population, usually intended to represent the population in a research study
Parameter
A value that describes a population.
Statistic
A value that describes a sample
Datum (raw score/score)
A singular measurement/observation
Descriptive Statistics
Statistical procedures used to summarize, organize, and simplify data
Inferential Statistics
Methods that use sample data to make general statements about a population
Sampling Error
Difference between a population parameter and a sample statistic used to estimate it
What is a statistic derived from?
Derived from measurements of the individuals in the sample
what is an issue with using a sample?
Provides limited information about the population
Cofounded
Factors other than the independent variable that may cause a result
Independent Variable
Variable that is manipulated by the researcher
Dependent Variable
One that is observed to assess the effect of the treatment
Control Condition
Do not receive the experimental treatment, they either receive no treatment, a neutral, placebo treatment
Experimental Condition
Receive the experimental treatment
Quasi- independent variable
“independent variable” that is used to create the
different groups of scores in a nonexperimental study
What is the correlational method? (One Group, Two variables)
Two different variables are observed to determine whether there is a relationship between them
What is a limitation of the correlational method?
Does not provide an explanation for the relationship between the variables
What is the experimental method?
One variable is manipulated while another variable is observed and measured
What is the goal of an experimental study?
Demonstrate a cause-and-effect relationship between two variables
What are the two characteristics of an experimental study?
1) Manipulation: Researcher manipulates one variable and observes the second variable to see if the manipulation has caused a change to occur
2) Control: Researcher must control certain variables to ensure the extraneous variables do not influence the relationship being examined
What are the two general categories of variables that researchers must consider?
1) Participant Variables: Described as the differing individual characteristics that may impact how a participant responds in an experiment
2) Environmental Variables: Factors (variables) that exist in an individual’s physical environment that influence behavior.
What are three techniques researchers use to control other variables?
1) Random Assignment: The use of chance procedures to ensure that each participant has the same opportunity to be assigned to any given group.
2) Matching: Ensure equivalent groups or equivalent environments.
3) Holding variables constant: An example of this is having on 10 year old boys participating in a study which means age and gender are held constant
What is a non-experimental method?
Research that lacks the manipulation of an independent variable, random assignment of participants to conditions or orders of conditions, or both
What are two examples of non-experimental research methods?
1) Non-equivalent groups
2) Pre-post Studies
Non-equivalent groups
One where the assignment of participants to groups is not controlled by the investigator
Pre-post studies
1) Measures outcomes in a group of participants before introducing a product or other intervention, and then again afterwards
2) Researchers have no control over variables that change with time
Constructs
Any complex psychological concept (love, honesty, fear)
Operational Definition
The statement of procedures the researcher is going to use in order to measure a specific variable
Discrete Variables
Consists of separate, indivisible categories. No values can exist between two neighboring categories
Continuous Variables
Infinite number of possible values that fall between any two observed values (time, height, weight)
Real limits
Boundaries of intervals for scores that are represented on a continuous number line
Upper Real Limit
Top of the interval
Lower Real Limit
Bottom of the interval
What does a nominal scale consist of?
- Consists of a set of categories that have different names
- ns.
Measurement on a nominal scale label and categorize observations but do not _________
make quantitative distinctions between observations.
What does an ordinal scale consist of?
Consists of a set of categories that are organized in an ordered sequence
Measurements on an ordinal scale rank observations in terms what?
Size and magnitude
What does an Interval Scale consist of?
Consists of ordered categories that are all intervals of exactly the same size
- Equal differences between numbers on scale reflect equal differences in magnitude
What does the zero point on the interval scale represent?
It is arbitrary and does not indicate a zero amount of the variable being measured
Examples of Interval Scale
Celsius and Fahrenheit
A ratio scale is a ____ scale with the additional feature of an absolute _______
interval; absolute
In a ratio scale, do the numbers reflect ratios of magnitude?
Yes
Examples of ratio scales
physical measures such as height, weight, enzyme activity and reaction rates
Add/Substract
Interval and Ratio
Multiply/Divide
Ratio
