Displaying Data:Graphing

“A Picture is Worth a 1,000 Words”

Components of a Graph

Figure Number (e.g., Figure 2.1)TitleLabel Axes (include units)Graph should be large enough to read and data should fill the graph spaceData SourceAuthor(s) Name, Date PublishedNeatness counts!Learn to use Microsoft ExcelChoose appropriate type of graph

Don’t Waste Space!

World Grain Stocks, 1960-2004

050

100150200250300350400

1960 2010 2060

Year

Days of

Consumption

Components of a Graph

Figure Number (e.g., Figure 2.1)TitleLabel Axes (include units)Graph should be large enough to read and data should fill the graph spaceData SourceAuthor(s) Name, Date PublishedNeatness counts!Learn to use Microsoft ExcelChoose appropriate type of graph

Scatter Plot

World Grain Stocks, 1960-2004

0

20

40

60

80

100

120

140

1960 1970 1980 1990 2000 2010

Year

Days of

Consumption

Line GraphWorld Grain Stocks, 1960-2004

0

20

40

60

80

100

120

140

1960 1970 1980 1990 2000 2010

Year

Days of

Consumption

Column/Bar Graph

World Grain Stocks, 1960-2004

020406080

100120140

196019631966196919721975197819811984198719901993199619992002Year

Days of

Consumption

Pie Graph

Figure 1. Soil Texture For Site F1(Robinswood Forest)

%Sand

%Clay

%Silt %Sand

%Silt

%Clay

Prepared by Seahawks, from soil sample collected on Bovember 3, 2004.

Choose Graph Type Carefully

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Statistics

Calculating Averages and Standard Deviations

Average & Standard Deviation

Average: The value obtained by dividing the sum of a set of quantities by the number of quantities in the set. (Also the “mean value”.)

Standard Deviation: The standard deviation is a measure of how spread out your data are.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

See worksheet on how to calculate Standard Deviation.

Median: The number dividing the higher half of a sample from the lower half.

Calculating Standard Deviation for Temperature

a) Find the average air temperature.b) Find the difference between the air

temp for each sample and the average – let’s call this X. For example, if sample 1 was 11.2°C and the average air temperature was 12.0°C, then X1 = 11.2-12.0 = -0.8°C.

c) Square X. So in our example X12 = (-

0.8)2 = 0.64°C2

d) Repeat the above step for all samples.

e) Add up the X2 values for all samples.f) Divide the value obtained in (e) by

the total number of samples minus 1 (n-1). If there were 14 sample then (n-1) = 13.

g) Take the square root of the answer you obtained in step (f). This number value is the standard deviation.

InterpretationAverage ± 1 Standard Deviation

--> 68% of the data

Average ± 2 Standard Deviations--> 95% of the data

Average ± 3 Standard Deviations--> Almost all of the data

Calculate Average and Standard Deviation for Moisture and Organic

Content(and include in table of data)

Soils Lab

What is due

Lab Reports

a) Titleb) Abstractc) Introductiond) Background

Informatione) Methodsf) Resultsg) Discussion

(Conclusion)h) Referencesi) Appendix

Introduction(One per group - typed)

a) A one page introduction to the lab report (One per group - typed)

b) A map of the study region with ALL the sample sites marked. (One per group)

Results (One per group - typed)1. A one paragraph description for each the

soils you analyzed. These descriptions should reference the table and graphs below. Be sure to describe the soil, as well as the area from which it was collected.

2. A table summarizing all of the soil data collected by your study (4-6 samples). Be sure to include a summary of all of the data collected (soil color, soil texture, moisture content, organic content, pH, nitrogen, phosphorous, potassium, and lead, etc.).

3. Bar graph of soil moisture data and organic content from all samples analyses by your study (4-6 samples). Be sure to include all the components of a graph and put all the data on the same graph. (One per group)

4. Pie charts for the distribution of grain sizes (sand, silt, clay) for the samples used in your study (4-6 samples). .

Conclusions(One per group - typed)

Write a 2 page discussion of the class study. Remember that you have already described your results in the data section above. For this part of the report, you want to describe what your data means, and how your samples compare to others analyzed by other groups. Be sure to think about the questions on the lab handout.

Appendix (One per group)1. A list (handwritten is OK) of what

each team member contributed to the lab.

2. All Raw Data sheets (Tables of data in this lab)