Chap 3 Measures of Variability Flashcards
Define Boxplot
A graphical representation of the distribution of the scores on a variable that includes the range, the median, and the interquartile range.
Define Interquartile Range (IQR)
The difference b/w the 75th (3rd q) percentile and the 25th(1st q) percentile scores in a distribution.
Define Range
The difference b/w the largest score and the smallest score of a distribution.
Define Squared deviation
The difference b/w an individual score in a distribution and the mean for the distribution, squared.
Define: Sum of squared deviations (sum of squares)
The sum of each squared deviation for all of the cases in the sample
Define Variance
The sum of the squared deviations divided by the number of cases in the population, or by the number of cases minus one in the sample
What does this symbol mean μ ?
The population mean
What does this symbol mean X?
An individual score in a distribution
What does this symbol mean s2?
The sample variance
What does this symbol mean s?
The sample standard deviation
What does this symbol mean σ
The population standard deviation
What does this symbol mean σ2
The population variance
What does this symbol mean SS
The sum of squares, or sum of squared deviations
What does this symbol mean n
The number of cases in the sample
What does this symbol mean N
The number of cases in a population
