2TABLES AND FIGURESResults of scientific studies in both primary and secondary literature are summarized for presentation in appropriate Tables and Figures which should clearly show key findings.
3Graph or Table?If the data shows pronounced trends that would make an interesting picture, use a graph. If no such trends exist, use a table.
4Graph or Table?With graphs, differences between variables and groups are easily seen ("a picture is worth a thousand words”).
5Graph or Table?Tables are preferred for presenting exact numbers.
6Graph or Table?Tables can accommodate information that graphs cannot (such as lists of species with their collection sites).
7General Rules for Tables and Figures Tables and Figures appearing in a paper are numbered in the sequence by which they are referred, starting with Table 1 or Figure 1.Both are referred to in the text.Germination rates were significantly higher after 24 hr water soak than in the control (Fig. 1) .
8General Rules for Tables and Figures Figure is abbreviated Fig. Table is not abbreviated.DNA sequence homologies for the purple gene from the four congeners (Table 1) show a strong similarity, differing at most by 4 base pairs.
9General Rules for Tables and Figures In addition to a name (Fig. X or Table Y), every figure or table has a title. The title goes above the body of the Table. Like titles of articles, they are a single, concise sentence. A legend goes below or beside a Figure. A legend may be one sentence or a few that concisely describe the figure.
19Descriptive LegendsEach figure will have an accompanying legend which describes the displayed results and should give other pertinent, clarifying information (key to abbreviations, sample size, statistical results, etc.).Enough information must be given so that the figure can be understood without reading the paper.
20Types of Graphs Line Graph Plots of a series of related values that depict a change in Y as a function of X.Shows trends and changes over time
21Types of Graphs Bar Graph Used to compare the value of a variable (usually a summary value such as a mean) among two or more groups of measurementsOften have error bars to show the SD or SEM for each group
22Types of Graphs Histogram A type of bar graph that shows the frequency of occurrence of data values for a sample variable.Important in describing populations, e.g.,size and age distributions
23Types of Graphs Scatterplot Plots plots of X,Y coordinates showing the relationship between two variablesShows if the variables change in value together in a consistent way. In this example, tree height appears to be dependent upon age.
24Types of Graphs Pie Chart Ubiquitous in business and mass media, but rarely used in scientific publications because it is often difficult to compare different sections of a given chart to each other.Numbers can be added (as in the example) to enhance readability
25Dependent vs Independent Variable The independent variable is the characteristic manipulated by the scientist (or nature) during the experiment. By convention, it is placed on the X axis.The independent variable answers the question “What do I change?”.
26Dependent vs Independent Variable The dependent variable is the characteristic affected by the manipulation of the independent variable. By convention, it is placed on the Y axis.The dependent variable answers the question “What do I observe?”.