Nitrate Levels in the Rock Creek Park Watershed, Washington DC, 1: Measures of Central Tendency
This material is based upon work supported by the National Science Foundation under Grant Number NSF DUE-0836566. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
- Work with nitrate (main part of module) and total phosphorus (end of module assignment) data from 11 stations in the Rock Creek watershed for 2006 and 2007 (201-row spreadsheet, with data grouped by month).
- Develop a graph that plots the measured values month by month in order to see the range each month, along with the run of monthly means and medians.
- Explore the meaning of mean, median and mode from a histogram of the positively skewed total data set.
- Read introductory slides on nutrients, eutrophication, and Washington DC's Rock Creek Park, one of the largest urban parks in the world.
In the process the students will:
- Get experience with the three main measures of central tendency: mean, median, and mode.
- See how measures of central tendency are positioned in a skewed distribution.
- Gain experience producing a moderately complicated scatter plot to show a run of monthly data and their summary monthly statistics.
- See an example of water-quality monitoring in an urban park.
Context for Use
This module is designed for potential use in the Geology of National Parks service course at USF. The course is offered as an online course every semester. It includes readings from Parks and Plates, weekly quizzes based on that textbook, and weekly student activities designed to align the course with the University's general education requirements. This module is intended to be one of those activities, with the specific goal of meeting the gen-ed quantitative literacy dimension.
Description and Teaching Materials
The module is a PowerPoint presentation with embedded spreadsheets. Click on the link below to download a copy of the module.
PowerPoint SSACgnp.TD367.MCR1.5 (PowerPoint 9.3MB Jun1 13)
Optimal results are achieved with Microsoft Office 2007 or later; the module will function in earlier versions with slight cosmetic compromises. If the embedded spreadsheets are not visible, save the PowerPoint file to disk and open it from there.
The above PowerPoint presentation file is the student version of the module. It includes a template for students to use to complete the spreadsheet(s) and answer the end-of-module questions, and then turn in for grading.
An instructor version is available by request. The instructor version includes the completed spreadsheet. Send your request to Len Vacher (firstname.lastname@example.org) by filling out and submitting the Instructor Module Request Form.
Teaching Notes and Tips
There is a slide at the end of the presentation that contains end-of-module questions. The end-of-module questions can be used to examine student understanding and learning gains from the module. Pre/post test, pre/post test answer key, and answer key for end-of-module questions are at the end of the instructor version of the module.
References and Resources
Carruthers, T., S. Carter, L.N. Florkowski, J. Runde, and B. Dennison. 2009. Rock Creek Park Natural Resource Condition Assessment. Natural Resource Report NPS/NCRN/NRR-2009/109. Natural Resource Program Center, Fort Collins, CO.
US National Park Service (NPS)
Rock Creek Park
http://biology.usgs.gov/ - Biological Informatics Program - Vegetation Characterization Program