APES 110_Gizmo-Estimating Population Size_2021 - High School

1. A jar contains 100 marbles total. Some are black. If you pull 4 marbles out and 1 is black, how many out of the 100 marbles would you guess are black? I would guess around 25. Explain. The reason I would guess 25 is because ¼ is the ratio of black marbles to other marbles being pulled out of 100 and ¼ of 100 is 25. 2. A different jar has 100 black marbles. (The total number of marbles is unknown.) If you pull 4 marbles out and 1 is black, what is your guess for the total number of marbles? 400 Explain. I would say 400, because ¼ of 400 is 100. Gizmo Warm-up In the Estimating Population Size Gizmo, you will estimate the total number of fish in a pond. You will do this by tagging and releasing a certain number of fish, and then “recapturing” some. To change the number of fish to tag or catch, drag the slider, or click on the number in the text field next to a slider, type a new value, and hit Enter. 1. Suppose a scientist tags 100 fish, and releases them. (Set the Tagged fish in pond to 100 to show this.) Later, a fisherman catches 50 fish from the same pond. (Set Fish to catch to 50 to show this.) The fisherman’s catch is a sample of all fish in the pond...