Factual Information - Graph Interpretation

How many months of air quality were measured & displayed in this graph?

The air quality of how many major cities was measured & displayed in this graph?

Which city is represented from the United States?

What specific gas was measured in this study?

What was the first year that astronauts were selected?

What was the first year that female astronauts were selected?

In what year were an equal number of male and female astronauts chosen?

In what year were 12% of the astronauts chosen women?

During what range of years was this data collected?

During 2017 the lowest number of airplane accidents occured. How many were there?