Unit 12

• Bar Graph


  A graph using bars to depict frequencies of responses, percentages, or means in two or more groups
• Central Tendency


  A single number or value that attempts to summarize all of the data, describing the typical score of where most of the scores fall
• Cohen's d


  An effect size estimate that is the standardized mean difference in scores between two groups
• Correlation Coefficient


  A statistic that describes how strongly two variables are related to one another and the degree that they covary
• Criterion Variable


  The outcome variable that is being predicted in a regression analysis
• Descriptive Statistic


  Statistics that describe and summarize the data collected

  • includes - central tendency, variability, and covariation
• Effect size


  The magnitude of an effect observed, either the extent to which two variables are associated or the size of the difference in scores between groups
• Frequency distribution


  A representation of how often each score was observed, arranged from lowest to highest score
• Frequency Polygons


  Graphs of frequencies for continuous variables, where the frequency of each score is plotted on the vertical axis and these points are connected by straight lines
• Mean


  Obtained by summing the scores and then dividing that sum by the number of scores

  • Used only for interval and ratio data
• Median


  The middle score in the distribution

  • Used for continuous variables and ordinal scales
• Mode


  The most frequent score in a distribution
• Multiple Correlation


  A correlation between a combined set of predictor variables and one criterion variable
• Multiple Regression


  An extension of the correlation technique that models the extent to which one or more predictor variables are related to one criterion variable
• Normal Distribution


  A prevalent distribution of scores for continuous variables where the majority of scores cluster around the mean, with fewer scores the farther away from the mean
• Outliers


  scores that are very different from the rest of the scores in a dataset
• Partial Correlation


  The correlation between two variables with the influence of a third variable statistically controlled
• Pie Chart


  A Circular graph that shows data as different slices
• Predictor Variable


  The variable used to predict changes in the criterion variable in a regression analysis
• Regression Equation


  Represents a line drawn to best fit a set of data points, allowing for one to predict the values of one variable based on another
• Restriction of Range


  When only a subject of a variables possible values are sampled or observed, which can lead to misleading null or attanuted correlations
• Scatterplot


  A graph of the relationship between two variables where pairs of scores are plotted on the x-axis

  • shows relationship between two variables
• Squared Correlation Coefficient


  A correlation coefficient that had been multiplied by itself resulting in a value that reflects the proportion of variance shared between the two variables.
• Squared Multiple Correlation Coefficient


  The proportion of variance in the criterion that can be explained bt the combined set of predictors for multiple correlation
• Variability


  The amount of dispersion for scores around the central value
• Variance


  A measure of the variability of scores about a mean