Chapter 2: Understanding Averages: Means to an End Flashcards
Average
The most representative score in a set of scores
Measures of Central Tendency
The Mean, the Median, and the Mode
Mean
A type of average calculated by summing values and dividing that sum by the number of values
Arithemetic Mean
A measure of central tendency calculated by summing all the scores and dividing by the number of scores. See Mean
Median
The midpoint in a set of values, such that 50% of the cases in a distribution fall below the median and 50% fall above it
Percentile Ranks
The percentage of cases equal to and below a particular score in a distribution or set of scores
Skew
The quality of a distribution that defines the disproportionate frequency of certain scores. A longer right tail than left corresponds to a smaller number of occurrences at the high end of the distribution; this is a positively skewed distribution. A shorter right tail than left corresponds to a larger number of occurrences at the high end of the distribution; this is negatively skewed distribution.
Outliers
Those scores in a distribution tha are noticeably much more extreme than the majority of scores. Whether a score is an outlier or not is usually an arbitrary decision made by the researcher.
Mode
The most frequently occuring score in a distribution
Data Points
An observation
Scale of Measurement
Different ways of categorizing measurement outcomes: nominal, ordinal, interval, and ratio
Nominal Level of Measurement
The most gross level of measurement by which a variable’s value can be placed in one and only one category
Ordinal Level of Measurement
A level of measurement that places a variable’s value into a category and assigns that category an order with respect to other categories
Interval Level of Measurement
A level of measurement that places a variable’s values into categories that are equidistant from each other, as when points are evenly spaced along a scale
Ratio Level of Measurement
A level of measurement defined as having an absolute zero
