Make a frequency distribution for a set of data.
Frequency distributions summarize a set of data by tallying how often the values, or ranges of values, occur. For all but nominal-level data, they may also display information about cumulative frequency, percentage, and cumulative percentage.
Decide if a number is discrete or continuous.
Discrete numbers are whole numbers that answer the question “How many?” Continuous numbers can be fractional and answer the question “How much?” The number of decimal places reported for a continuous variable depends on the precision of the measuring instrument.
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The range within which a single continuous value, or an interval of continuous numbers, falls is bounded by the real limits of the interval.
Choose and make the appropriate graph for a frequency distribution.
Frequency distributions of discrete data are graphed with bar graphs; distributions of continuous data are graphed with histograms or frequency polygons.
Describe modality, skewness, and kurtosis for a frequency distribution.
Modality refers to how many high points there are in a data set. If a distribution is asymmetric, it is skewed, while kurtosis refers to how peaked or flat a distribution is.
Make a stem-and-leaf display.
Stem-and-leaf displays are a great way to summarize a set of data. They present the data compactly, like a grouped frequency distribution; keep all the details like an ungrouped frequency distribution; and show the shape, like a graph.