Psychological Research Flashcards
Independent variable
Variable manipulated by researcher
Dependent variable
Participants response
Continuous variable
Continuous variables have a continuum of possible values and involve measuring
Categorical variable
Groupings or categories of values
Discrete variables
Values restricted to whole numbers
Nominal Measures
Not ordered and have no numerical value - numbers are only used to classify an object - “tags” or “labels”
Nominal variables are usually “frequency” data and used for discrete variables
Ordinal Measures
Ordered catergories that reflect ranking of objects or events and used to represent things like freuqency, satisfaction, pain level etc.
Qualitative
Interval and Ratio Measures
Numerical scales - the order of variables is known as well as the difference between them.
The difference between these two measures - ratio have a true zero (and has highest level of specificity) whereas in interval the zero is arbitrary
3 main goals of the scientific approach
To describe, predict (future events and correlations) and understand (cause of phenomena)
Experimental research
Manipulates variables to assess cause and effect
Establish cause
What is operationalisation?
It is the process of turning abstract concepts into measurable observations. It involves defining how a concept/variable can be measured, observed, or manipulated.
Descriptive research
Research methods that attempt to describe phenomena - not cause and effect. Use observation and case studies
(Describe)
Correlational research
Examines the extent to which 2 or more variables are related and can be used to predict one another - cannot establish causation
(Predict)
Measures of central tendency
Used in descriptive statistics to identify the averages of a set of data - the three main measures are mean (average), median (middle number of data when in consecutive order) and mode (the most common value)
Normal distribution
Distribution of data that has roughly the same amount of data on either side of the middle and most common values in the middle - shown by symmetrical bell curve
What does it mean in a data set when the mean, mode and median are all the same?
The distribution of data is completely normal
What does range measure?
The variability which is shown by the difference between the highest and lowest values
Statistical significance
The likelihood that results of a study have occured by chance.
Effect size
Tells you how meaningful the relationship between variables or the difference between groups is.
Large effect sizes mean the difference is important; small effect sizes mean the difference is unimportant
Confidence intervals
Range of values that shows the probability that an unknown population parameter falls within the the interval (population mean) with a certain level of confidence - usually 95%.
What is μ (mu)?
Used to denote the population mean
Correlation coefficient
Measures the extent to which two variables are related
Quasi-experimental designs
Design that has the logic of experimental methods but lacks control of variables - attempts to establish a cause-and-effect relationship
Analysis of variance (AWOL)
Statistical procedure used to compare the means of two or more groups
Chi-square test
Test of statistical significance when both independent and dependent variables are categorical
t test
test of statistical significance when comparing mean scores of two groups to find if there is a significant difference
p value
The probability that findings happened by chance.
A p value of 0.05 or lower means results are significant.
Measure
A concrete means in determining the value of a variable
Interval Estimation
Provides a range of values based on observation from 1 sample and gives information about the closesness to unknown population parameter
