Question

What kind of display would be the best way to represent the data below?

Type of species
Critically endangered (%)
Endangered or vulnerable (%)
Plants
13
70
Invertebrates
0
35
Freshwater fish
9
37
Amphibians
7
30
Reptiles
5
28
Birds
0
12
Mammals
2
21
bar graph
pie chart
line graph
scatter plot

Answer 1

Best: a bar graph — specifically a grouped (side-by-side) bar chart showing two bars per species (one for Critically endangered %, one for Endangered/vulnerable %).

Why: it makes it easy to compare the two percentages across the different species categories. A pie chart is inappropriate (these values are not parts of a single 100% whole), a line graph is for trends/continuous x-axes, and a scatter plot is for relationships between two numeric variables.

Tips: use distinct colors and a legend, start the y-axis at 0 with percent labels, and order species to highlight patterns (e.g., by total threatened or by one of the series). If you want to show the combined threat level, consider a stacked bar as an alternative.