PS296 Week 2A- Chapter 3 (Displaying Data)
Displays of Data
• Frequency distribution:
– A distribution in which the values of the dependent variable are tabled or plotted against
their Frequency of occurrence
– How many times each score or value occurred in a set of data (a distribution of scores)
Frequency Tables
• Frequency table for a categorical variable:
– usually nominal or ordinal data
• How many males, how many females in a class
Graphical representations of data
• We can describe a set of numbers in pictorial form
• Graphical presentation to demonstrate data
• Describe what scores occurred, frequency of each score
Bar graph
• Bar graph:
– A graph in which the frequency ( f ) of occurrence of different values of X is represented
by the height of a bar
• Vertical bar over each value on the X axis
• Adjacent bars do not touch
• Height of the bar indicates the corresponding value’s frequency
Histogram • Histogram:
– Graph in which a rectangle is used to represent frequencies of observations within each
interval
• Use

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