One method for simplifying and organizing data is to construct a
frequency distribution
an organized tabulation showing exactly how many individuals are located in each category on the scale of measurement.
frequency distribution
In the X column(frequency distribution), values are listed from the
highest to lowest, without skipping any.
For the frequency column (frequency distribution)
tallies are determined for each value
The sum of the frequencies should equal
N
consists of at least two columns - one listing categories on the scale of measurement (X) and another for frequency (f).
frequency distribution table
The percentage is found by multiplying _____. The sum of the percentage column is 100%.
p by 100
A third column can be used for the proportion (p) for each category:
p = f/N
When a frequency distribution table lists all of the individual categories (X values) it is called a _____
regular frequency distribution
To remedy situations where a list of all the X values would be quite long - too long to be a “simple” presentation of the data.
grouped frequency distribution
In a grouped table, the X column lists groups of scores, called _____, rather than individual values.
class intervals
In a frequency distribution graph, the score categories (X values) are listed on the _____ and the frequencies are listed on the _____.
X axis and Y axis
a bar is centered above each score (or class interval) so that the height of the bar corresponds to the frequency and the width extends to the real limits, so that adjacent bars touch.
Historgram
a dot is centered above each score so that the height of the dot corresponds to the frequency. The dots are then connected by straight lines.
Polygon
When the score categories (X values) are measurements from a nominal or an ordinal scale. just like a histogram except that gaps or spaces are left between adjacent bars.
Bar Graph
In a _____ distribution, the scores tend to pile up on the left side of the distribution with the tail tapering off to the right.
positively skewed
In a _____ distribution, the scores tend to pile up on the right side and the tail points to the left.
negatively skewed
When an X value is described by its rank, it is called a
Percentile
_____: consisting of the first digit.
_____: final digit
Stem & Leaf
To find percentiles and percentile ranks, two columns are placed in the frequency distribution table: one is for _____ and the other is for ______
Cumulative frequency (cf) and cumulative percentage (c%)
