PSYC 310 Ch 5 Flashcards
Table with all of the scores listed along with the frequency with which each occurs
Frequency Distribution
Table with scores grouped into intervals and listed along with the frequency of scores in each interval
Class Interval Frequency Distribution
Categorical variable for which each value represents a discrete category
Qualitative Variable
Graphical representation of a frequency distribution in which vertical bars are centered above each category along the x-axis and are separated from each other by a space, indicating that the levels of the variable represent distinct, unrelated categories
Bar Graph
Variable with the scores representing a change in quantity
Quantitative Variable
Graphical representation of a frequency distribution in which vertical bars centered above scores on the x-axis touch each other to indicate that the scores on the variable represent related, increasing values
Histogram
Line graph of the frequencies of individual scores
Frequency Polygon
Numerical measures that describe a distribution by providing information on the central tendency, width, and the shape of the distribution
Descriptive Statistics
Number that characterizes the “middleness” of an entire distribution
Measure of Central Tendency
Average
Mean
Middle score in a distribution after the scores have been arranged from highest to lowest
Median
Score in a distribution that occurs the most amount of times
Mode
Number that indicates the degree to which scores are either clustered or spread out in a distribution
Measure of Variation
Difference between the lowest and highest scores in a distribution
Range
Average difference between the scores in the distribution and the mean or central point of the distribution; square root of the average squared deviation from the mean
Standard Deviation
Indicates the average difference between the scores in a distribution and the mean of the distribution; alternative to SD
Average Deviation
Standard Deviation Squared
Variance
Symmetrical, bell-shaped frequency polygon representing a normal distribution
Normal Curve
Theoretical frequency distribution that has certain special characteristics
Normal Distribution
How flat or peaked a normal distribution is
Kurtosis
Normal curves that have peaks of medium height and distributions that are moderate in breadth
Mesokurtic
Normal curves that are tall and thin, with only a few scores in the middle of the distribution having a high frequency
Leptokurtic
Normal curves that are short and more dispersed (broader)
Platykurtic
Distribution with peak to the left of the center point, and the tail extends towards the right, or in the positive direction
Positively Skewed Distribution
Distribution with peak to the right of the center point, and the tail extends toward the left, or in the negative direction
Negatively Skewed Distribution
Number that indicates how many standard deviation units a raw score is from the mean of a distribution
Z-score (Standard Score)
Normal distribution with a mean of 0 and a standard deviation of 1
Standard Normal Distribution
Expected relative frequency of a particular outcome
Probability
Dividing the squared deviation scores by N-1 rather than N, you are using ______ of the population standard deviation.
Unbiased Estimator
Score that indicates the percentage of people who scored at or below a given raw score
Percentile Rank
Interval & ratio
Mean
Ordinal, interval, & ratio
Median
Nominal, ordinal, interval, or ratio
Mode
