What does doubled-graph mean?

Answer 1

You use 2 colors for the bars so you can compare things. Maybe one color for male unemployment, and one color for female over several years. You can look to se trends for increasing and decreasing unemployment and you can see which consistently has a higher unemployment or if one sex had higher unemployment then maybe it switched to the other.

Answer 2

A double graph typically refers to a graph or chart that has two sets of data plotted, often with different scales or units of measurement. This allows for the comparison of two different variables or trends in one visualization.