Download Creating Histograms, Frequency Polygons, and Cumulative Frequency Polygons with SPSS - Pro and more Study notes Geography in PDF only on Docsity! 3190 Week 3 Graphing Data Stem & Leaf Diagram • An easy way to convert frequency distributions to a chart Cases (state values) Distribution of 1996 US state unemployment rates 2 9 3 1 2 5 5 8 4 0 1 1 2 2 3 3 4 5 6 6 6 9 9 9 5 0 1 1 1 1 2 2 2 3 3 3 4 4 5 6 6 7 9ou ps 6 0 1 2 2 4 5 7 7 2 5 8 8 1 G ro 2UNT Geog 3190, Wolverton Frequency Polygon • Converts a histogram to a line graph ll i f l i l f• A ows easy express on o mu t p e requency distributions on the same graph – Which is cumbersome with a histogram 5UNT Geog 3190, Wolverton Frequency Polygon, example Percentage Polygons for Lot Size (Phase I v. Phase II) 60.0% 70.0% 30.0% 40.0% 50.0% en ta ge o f T ot al 10.0% 20.0%Pe rc e 0.0% 1.5 2.5 3.5 4.5 5.5 6.5 Lot Area Category Midpoint (Acres) Phase I Phase II Does this frequency show a raw data or relative frequency distribution? 6UNT Geog 3190, Wolverton Cumulative Frequency Polygon • A frequency polygon that graphs frequency of cases in a group and frequency of cases in any lower groups I i ddi i• ts s a t ve • For each group you graph its frequency and add the frequency of all lower groups to it. UNT Geog 3190, Wolverton 7 Cumulative Frequency Polygon
Cumulative Distribution of 1996 US state unemployment rates
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Graphs in SPSS Sorting & Grouping • The easiest way to group data is to sort data into an ordered array • Then insert a new variable and use it as a “ i i bl ”group ng var a e • This is important for graphs and some inferential tests later in the class Sorting Now each deer is ordered from lowest to highest in terms of weight; notice many f th do ese are oes The heaviest deer (if you scroll down) will be bucks Grouping Highlight the weight variable Then right click and select insert variables Grouping New variable; go to “variable view” and name it “grouping” Histogram Go to Graphs, Legacy Dialogs, Histogram We are going to make a histogram based on our weight groups You should make a frequency distribution on your own to provide a complementary table Histogram Unweighted statistics Mean 60.3521 Std. Deviation 18.14458 Variance 329.226 Weighted statistics Frequency Polygon Go to Graphs, Legacy Dialogs, Line Select “simple” & push “define” Cumulative Frequency Polygon
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Histogram of our raw data Histograms with such small groups as derived from raw data (here “weight” instead of “grouping”) may not be useful with small samples But here we have such a large sample that it is quite meaningful
