Chapter 2 & 3- Data Types and Visualization Flashcards
frequency distribution
a summary display for a distribution of data organized or summarized in terms of how often a category, score, or range of scores occurs.
simple frequency distribution
a summary display for (1) the frequency of each individual score or category (ungrouped data) in a distribution or (2) the frequency of scores falling within defined groups or intervals (grouped data) in a distribution.
Grouped data
a set of scores distributed into intervals, where the frequency of each score can fall into any given interval.
interval
a discrete range of values within which the frequency of a subset of scores is contained.
To construct a simple frequency distribution for grouped data (3 steps)
Step 1: Find the real range.
Step 2: Find the interval width.
Step 3: Construct the frequency distribution.
Interval width= Real range/ number of intervals
real range
one more than the difference between the largest and smallest values in a data set
interval width or class width
the range of values contained in each interval of a grouped frequency distribution.
Interval boundaries
the upper and lower limits for each interval in a grouped frequency distribution.
The lower boundary is the smallest value in each interval, and the upper boundary is the largest value in each interval.
four rules for creating a simple frequency distribution:
Each interval is defined (it has a lower and upper boundary). Intervals such as “or more” or “less than” should not be expressed.
Each interval is equidistant (the interval width is the same for each interval).
No interval overlaps (the same score cannot occur in more than one interval).
All values are rounded to the same degree of accuracy measured in the original data (or to the ones place for the data listed in Table 2.1).
open interval, or open class
an interval with no defined upper or lower boundary
Outliers
extreme scores that fall substantially above or below most of the scores in a particular data set.
cumulative frequency distribution
a summary display that distributes the sum of frequencies across a series of intervals.
relative frequency distribution
a summary display that distributes the proportion of scores in each interval. It is computed as the frequency in each interval divided by the total number of frequencies recorded.
proportion
a part or portion of all measured data. The sum of all proportions for a distribution of scores is 1.0.
relative percent distribution
a summary display that distributes the percentage of scores occurring in each interval relative to all scores distributed.
cumulative relative frequency distribution
a summary display that distributes the sum of relative frequencies across a series of intervals.
cumulative percent distribution
a summary display that distributes the sum of relative percents across a series of intervals.
Cumulative relative frequencies and cumulative percents are a sum of the proportion and percent of scores, respectively, across intervals. These sum to 1.00 or 100%, respectively.