Quick Reference Guide
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The Data Collection and Processing part of a report should include three main aspects:
- Recording the raw data.
- Processing the data.
- Presenting the processed data.
Data Collection
In Data Collection your goal is to communicate clearly all data obtained during the investigation. Data may include tables with measurements and readings, diagrams, descriptions or photographs. All data must be clearly labeled and easy to understand.
Different types of data are presented differently.
- Quantitative data need to be in S.I. ("metric") units and must be consistent throughout. Any uncertainties in the data must be clearly shown.
- Diagrams need to be clear and large enough to see details. Biology diagrams must be in pencil.
- It is a good practice to keep a raw data sheet for descriptive observations, collection of data, and weaknesses/improvements noted in the procedure during labs. Descriptions should be precise and informative. For example, was the solution after the test "blue" or was it "clear, deep, brilliant royal blue"? Or, maybe it was "cloudy, greenish blue"? Carefully describe how things felt, looked, smelled, or sounded.
Your teachers will help you with the details of how to do all of these things for the laboratory investigations that you will be doing in your classes.
Tables require a title ABOVE the table. The title will generally include the variables being graphed. Here are some examples of good table titles:
Table 1: The Acceleration of a Cart as Mass is Varied
Table 1: Rate of Oxygen Production vs. Enzyme Concentration
Table 2: Number of Seeds Germinating as pH Levels are VariedTables also need a numbered label and a caption explaining important points below the table. Labels and captions should be put in a smaller italicized font. Tables and figures are refered to in the text by the numbered label, i.e. "The data in Table 1 clearly show that as more force is applied the acceleration of the cart is increased".
Rules for Tables
- The reader should be able to understand tables without referring to the text.
- All tables need a title and should have a numbered label and a caption to explain important points, symbols, abbreviations, or special methods. The caption is in a smaller font and placed below the table.
- Avoid having tables that are not referred to in the report.
- Including some processed data such as averages in a raw data table is acceptable.
- Uncertainties are estimates and should be rounded to one significant figure ( ± 0.34 should be rounded to ± 0.3). The data in tables should be rounded to match the uncertainty ( 14.37 ± 0.3 should be rounded to 14.4 ± 0.3).
- Label columns and rows with the quantity being measured, the units of measurement, and the uncertainty of the measurement.
- Place units in the headings -- not in the individual cells of the table.
- NEVER split data tables over two pages. Titles must be on the same page as the table.
- It is good practice to center the data in the columns and the titles of the columns over each other.
To summarize, a table needs a title, label and caption, quantities, units and uncertainties for each column, and clear organization and formatting.
Data Tables Here are some examples of Data Tables.
Some types of data are more appropriately presented in a figure. This includes data and observations in the form of photographs, drawings, diagrams and graphs. Figures include photographs or diagrams of experimental set-ups; drawings of plants, cells, or microbes; photographs or diagrams of experimental results; and computer-generated graphs showing collected data.
Rules for Figures
- Figures must be clear and easy to understand.
- Figures must have numbered labels and captions which describe the figure and any important points, such as a legend (key) explaining any unusual symbols, abbreviations, or special methods used. Some examples of good labels and captions follow:
- Figure 1: Bean Seedlings after 1 Week of Growth. The seedlings now have fully developed leaves and root systems.
- Figure 2: Onion Epidermal Cells Stained with Iodine
- Figure 3: Results of Sugar Tests on Unknown Samples. Note that the result for the last sample is significantly lower than the rest.
- Figure 4: The velocity-time graph for the ball thrown in the air in trial 1. The slope of the graph is the acceleration of the ball due to gravity.
- The label and caption go beneath the figure.
- Only figures that will be discussed in the report should be included.
- All original drawings should be done in pencil.
- Drawings must be large enough to show clear detail.
- Stippling (drawing with short strokes or dots) on biological diagrams is better than shading.
- Drawings should be done on unlined paper.
- Drawings should be realistic.
- Composite diagrams are acceptable.
To summarize, a figure needs to be clear and easy to understand, and needs a label and caption.
Figures Here are some examples of figures.
Data Processing
Sample Calculations
This section of a lab research report should show how you used your raw data to answer your research question. Often, the measurements that you make during the experiment cannot directly provide an answer to your research question, so you need to perform some calculations using the raw data. The equations you use and the ways you rearrange the data will depend on the investigation. You will be learning how to process data appropriately in lab investigations throughout the year.
For continuous data in biology investigations, a t-test (available at graphpad.com) is used to determine if the independent variable had a significant effect on the dependent variable. For categorical data, use a chi-square test to do the same. For a tutorial on how to choose and use the appropriate test, go here.
One example of all significant calculations or manipulations performed on the raw data should be shown in a sub-section entitled “Sample Calculations”. Sample Calculations should be shown for one typical data value. The trial or value used should be clearly stated.
Sample Calculations start with the equation used to process the data. The appropriate values with units are then substituted into the equation. Finally the result of the calculation should be shown. The calculation of the uncertainty in your processed data should also be shown, where appropriate.
In cases where your data was collected using a computer, it is usually appropriate to include a sample graph showing your reader how the data was derived from the computer-generated graph. Use the caption to explain how your data was derived from the graph (for example: slope, average, or y-intercept) and to identify which trial this graph is from. Follow the rules for presenting graphs given below.
Uncertainties Here are the general rules on how to determine and report on uncertainties in processed data.Sample Calculations Here is an example of what a good Sample Calculations section looks like.
Results
You must then present this processed data in a way that clearly answers your research question. Your processed data can usually be presented in a line graph, table, or diagram. Bar graphs or pie charts are also sometimes appropriate. Knowing the most appropriate way to present various types of results is one of the things you will be learning in your classes.
Graphs are often the most appropriate way to present your results. We will be using the Logger Pro graphing program for making graphs (some students may opt to use Microsoft Excel). A tutorial on Logger Pro has been included in this writing guide. Use it.
A good graph has certain characteristics.
- You must have a title telling what the graph is showing. A good title usually includes the independent and dependent variables.
- Each axis must have a label and units, telling what is being measured and the units of measurement. In general, the independent variable should go on the x-axis, and the dependent on the y-axis.
- The axes of the graph should be scaled appropriately, so that the data fills most of the space in the graph. A good rule of thumb is that the data should take up approximately 75% of the space in the graph.
- The graph should start from the origin (0,0) in most cases.
- Uncertainty bars should be included, when appropriate.
- A best-fit curve should be fitted to the data when appropriate, rather than connecting the dots. The values for the constants (slope and intercept) given in the Analysis Box for the curve fit should be adjusted to appropriate significant figures. (The computer default value is 4 significant figures, while data often have fewer significant figures than that).
- There should be a caption describing what is being shown on the graph, and discussing any important points that the reader should notice. These might include the meaning of the slope and intercepts or any interesting features in the data.
A graph is used to present the results of your investigation in a way that is easy to understand and interpret. It is often appropriate to have several graphs showing different aspects of your results. It is best if the final graph shows the independent and dependent variables manipulated to produce a straight line fit. This allows you to determine values for the slope and intercepts, which are usually meaningful.
Curve Fits Here is more in-depth information on how to choose and use a curve fit appropriate to your data.
Graph Presentation is an example of how to present your results graphically.