Visualizations

Visualizations

1. Contingency table

   • summarize categorical data
   • headings show variables

2. bar graphs

   • categorical data
   • x axis: categories; y axis: freq. (usually)
   • Gaps
   • can be grouped or stacked to show each level
   • categorical x categorical

3. histogram

   • numerical: put in bins
   • could to show relative abundance, distribution
   • no gaps
   • DISADV: hard to see numerical variables across groups
   • numeric

4. box plots

   • numerical: see median, variations
     • extreme: Q3 + 1.5 IQR;Q1 - 1.5IQR
       • whiskers DON'T include these (*)
   • can use for categorical and numerical
     • observational: groups are categorical variabels
     • experimental: groups are treatment factors
   • easy to compare groups;NOT for distribution
   • categorical x numeric; if one box then just numeric

5. scatter plots

   • show pattern bet 2 numerical variables when data from diff sampling units
     • each point diff sampling unit
   • numeric x numeric

6. line plot

   • data colletcted repeatedly from same sampling unit
   • diff colours for diff sampling units; connect data poins