A candy jar contains several small pieces of candy:
• 5 miniature peanut butter cups
• 7 dark chocolate candy bars
• 8 gummy worms
Roger randomly selected one piece of candy from the jar.
What is the probability in decimal form that the candy Roger selected was NOT a gummy worm?
There are a total of 5 + 7 + 8 = 20 pieces of candy in the jar.
There are 8 gummy worms, so there are 20 - 8 = <<20-8=12>>12 pieces of candy that are not gummy worms.
Therefore, the probability that the candy Roger selected was not a gummy worm is 12/20 = <<12/20=0.6>>0.6. Answer: \boxed{0.6}.