Central Tendency
Central tendency: statistic that tells us what sample as a whole, or average is like
3 measures of central tendency
o Mean: set of scores obtained by adding all scores and dividing by number of scores. Appropriate
indicator of central t
Scales of Measurement: A Review
Whenever variable is studied, theres operational definition of variable and must be 2 or more levels of
variable
4 scales of measurement: nominal, ordinal, interval and ratio
o Scale used to determine types of statistics
o Process evaluation evaluation, whether its attracting enough clients, and if staff is providing
planned services.
Research is important because we would not want to conclude that program itself is
ineffective if its the implementation of program that i
Nonequivalent Control Group Design
Nonequivalent control group design: employs separate control group but participants in two conditions
experimental group and control group arent equivalent
Differences become confounding variable that provide alternat
Effect Size
Effect size: general term that refers to strength of association between variables
Pearson r correlation coefficient is one indicator of effect size; indicates strength of linear association
between 2 variables
In experiment with 2 or more
Sampling Distributions
Binomial distribution: all statistical decisions are based on probability distributions
outcomes further from expected result are less likely if null hypothesis is correct
all statistical tests rely on sampling distributions to d
Structural Equation Modeling
Structural equation modeling (SEM): model is an expected pattern of relationships among a set of variables
o Proposed model is based on theory of how variables are causally related to one another
o After data collected, stati
Simple Main Effect of Type of Questioner
Tell us whether difference between knowledgeable and nave questioner is significant when question is
o 1. Unbiased
o 2. Misleading
Simple main effect of type of questioner is significant when question is misleadin
Reversal Designs
Basic issue in single case experiments is how to determine that manipulation of independent variable had
effect
Reversal designs: single case design in which treatment is introduced after baseline period and then
withdrawn during second
Increasing Number of Independent Variables: Factorial Designs
Typically, 2-3 independent variables are operating simultaneously
Researchers recognize that in an situation a number of variables are operating to affect behaviour
Factorial designs: design