# Statisticians are the Data Detectives of the XXI Century

First, letâ€™s watch a video that introduces the Latina scientist Claudia Solis-Lemus and her job as data scientist:

# Activity: Guess how many marbles of each color!

**Preparation:**Your teacher must prepare a paper bag or non-see-through container with 100 marbles of two colors (say red and blue). You cannot see how many marbles of each color are in the bag.- Do not have marbles? No worries! You can use small paper squares of two different colors.

**Instructions:**Without looking at the marbles, you should take out 5 marbles and count how many blue marbles you have out of 5. For example, you can count 4 blue marbles out of 5 for a proportion of 4/5. You will repeat this process 5 or 10 more times (the more, the better; why?) and you will average your proportions.**Result:**Your guess for the number of blue marbles will be the average proportion that you calculated. For example, if you had on average 4 out of 5 blue marbles, you would expect 4*100/5 = 80 blue marbles in total in the bag.- Take out the marbles and count them!
- How close was your guess?

# Impact in the World: Statistics helps Rainforest Biodiversity!

Just as we counted blue marbles, we can use statistics to count how many species of birds exist in a given rainforestâ€¦and how many species of frogs and insects. We can use our counts to determine if the rainforest is healthy (it has a great diversity of species) or not.

Read more abour our statistical work in the real world in the PBS Meet the Lab: the Data Decoders!