There are 100 fish hiding in this pond, in three different colors. Cast your line, keep track of what you catch, and use your sample to infer what's really down there — before you reveal the real pond.
Every fish you land goes on the line, in order.
Based only on your sample, how many of each color do you think are really in the pond of 100 fish? Fill in your best estimate for each, then lock it in.
Once you've locked in your inference, reveal the actual pond and see how your sample compares to reality.
This replaces the 100-counter bag activity: instead of pulling a physical counter, students "cast" for a fish drawn at random from a hidden 100-fish pond, then it swims right back in — so the pond's mix never changes while they fish (sampling with replacement, same as returning the counter to the bag).