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

Answer 1

A bar graph — specifically a grouped (side‑by‑side) bar chart — is best.

Why:
- You have categorical x values (species types) and numeric y values (percentages), and you want to compare two different percentages for each category. Grouped bars make those comparisons clear.
- Pie charts are for showing parts of a single whole (not suitable for repeating two-series comparisons across many categories).
- Line graphs imply a continuous/ordered x axis and trends; they’re not appropriate for unordered category comparisons.

Tip: use distinct colors with a legend for the two series, label the y‑axis as “%”, and consider ordering species by total threatened or one of the series to make patterns easier to see. (A stacked bar is an alternative if you want to show composition and total threatened together.)