STATISTICS & THE ENVIRONMENT

GOALS

1. oranize and describe data

2. use statistical summaries and graphs

3. calculate with fractions, decimals, and percents

4. judge whether or not samples are representative and random

5. read, interpret, and use information from maps or graphical displays of data

6. choose and use appropriate techniques to analyze data

7. make inferences based on data

8. make decisions based on statistical information and justify the decisions

SECTION SUMMARIES

SECTION A: PREPARING TO USE STATISTICS

1. Statistics is the science of collecting, organizing, and interpreting numerical facts that are called data.

2. Data can be produced by sampling a part of a population in order to gain information about the whole.

3. Contour maps and profiles, or vertical cross sections of a landscape are two-dimensional representations of a three dimensional situation. A contour line connects points that have the same height.

SECTION B: DATA ABOUT ENDANGERED FORESTS

1. In this section, students use a grid for estimating the area of an irregular shape. Area is measured in square units. In order to convert square centimeters to square metres, remember that 1 square metre is equal to 10,000 square centimetres.

2. We used a bar graph to estimate the percent in a particular category. Remember that a percent comes from a part to whole relationship (a relative comparison). Remember that an absolute comparison compares part to part and cannot be turned into a percent.

SECTION C: INTERPRETING DATA

1. Statistics and graphs work together in any data analysis. Graphs provide a visual picture of the data, while statistics summarize a characteristic of the data: typical values or the spread of the data.

2. Graphs can identify the center, the overall shape of the data, gaps, clusters, and outliers, while a statistic is a number that shows a count, a representative value in a set of data, or the three values of central tendency – mean, median, and mode.

3. The median (the middle number in the ordered data) is not affected by outliers. The mean (the sum of the data divided by the number of data points) is affected by outliers.

4. A good description of data should include the range (high # - low #) and the mean because the spread of the data will be important information.

SECTION D: DESCRIBING DATA

1. In this section we applied statistical tools and concepts to analyze and describe data. These tools and concepts can be a bar graph, stem-and-leaf plot, histogram, circle graph, stacked bar graph, scatterplot, mean, median, mode, range, clusters, and outliers ( observations falling outside the overall pattern of the data).

2. Fractions, decimals, and percents are used to make relative comparisons. We also find percents of percents. The given data involve some very large numbers to order and use along the axes of graphs.

SECTION E: LAND USE PLANS FOR MURRE ISLAND

1. This section requires the use of all previously learned statistical ideas, especially making inferences based on data, and making decisions based on statistical information.

2. The mathematics in this section focuses on the higher goals of organizing information, justifying plans, and making decisions.