Explain a time when you had to make a decision without all the relevant facts.
Pick a decision that you would not have all the facts for at the time of the decision. Make sure that you speak about all the different options you had and how you picked the best one out of what you had available. Talk about the results/takeaways.
For instance, I had to decide whether our organization was going to be involved in a new marketing campaign that used social media to advertise our products. At this point in time, our company did not have relevant information on how successful our previous social media marketing campaigns were. If we were to proceed, I was going to have dedicate at least one member on my team to its success. It would be time-consuming and if not successful, would take up a lot of productivity time. I decided to take part in the campaign because it was relatively inexpensive and the potential to gather information about best practices when launching them in the future. We ended up with a very successful marketing campaign with measurable results.