Internal Assessment: Lincoln Index/Population Estimating
Research Question: What effect does the number of marked specimens have on the accuracy of the Lincoln Index?
Experiment Procedure:
1. Count out 150 beans and pour the beans into your container. This number is N, the value you’ll be estimating.
2. Take out designated number of beans and set them aside. This represents, for example, trapping a certain number of animals. Mark each bean on both sides with a marker. Count how many beans you have marked, and record this number as n1. Your group will be assigned the number you will mark.
3. Pour all the marked beans back into your container and mix thoroughly. This represents releasing these marked animals back into the general population.
4. Now, take another handful of beans out, set them aside, and count them. This is your second capture: record this number as n2.
5. Of the n2 beans in the second handful, some of them will be marked and some won’t. (Note: if NONE of your beans are marked, then you can’t use this n2 value. Instead, you’ll need to pour this handful of beans back into the container and return to step 4.) Count how many in the second handful are marked. Record this number as m.
6. Pour your second handful (n) back into the container.
7. Repeat steps 4-6 ten times and record your data.
8. Enter your data into the class data base.
9. Now that you’ve gathered data for n1, n2, and m, you’re ready to calculate an estimate of N.
Use the formula :
N= (n1 x n2)/m
N = Estimated population
n1 = Original number marked
n2 = Number captured total
m = Number marked in n2
More information on the Lincoln index can be found on pages 30-31 of your textbook.
Using the class data, answer the research question through the writing of the internal assessment including the Data collection and processing (DCP) and the Discussion, evaluation, and conclusion (DEC). The rubric and information can be found on pages 319-322 of your textbook. This assignment should be typed. If this is difficult for you, talk to me before the due date. The laptops will be available in class on Monday and Tuesday (February 11 and 12)as well as time to work.
DUE DATE: Friday February 15, 2013
What should be in my write up?
1. Research Question
2. Recording Data: Show Data
3. Processing Data: Making calculations
4. Presenting Data: Making graphs
5. Discussing/Review: Discuss the Lincoln Index and data trends
6. Evaluate: Suggest strengths. weaknesses, and improvements
7. Conclusion: Conclusion supported with evidence from data
Directions for inserting the Lincoln Index formula in the excel spreadsheet:
1. Highlight cells F2 - F91.
2. Type in "=(C2*D2)/E2"
3. Hit Ctrl and Enter at the same time.
4. It should fill the table with the estimated population size.
In your lab write-up, you need to show one cacluation of the Lincoln Index showing your work.