2. The graph visualizes the statistical data with graphs, and represents the quantity with row height and area size, which is simpler and easier to understand than words and statistics.
There are many kinds of statistical charts, including bar chart, percentage bar chart, histogram, line chart and point chart. Taking scientific papers as an example, when comparing grouped data with different properties, we can choose a bar chart to explain the composition of each component, a circular chart or a percentage bar can be used as a histogram, and a line chart can be used to express the change of one thing and another, so as to express the correlation and trend of the two things.
Statistical chart has certain requirements for its structure [including legend, axis, number axis, legend (Sym error line)] and text citation, which are described below, and four commonly used frequency histograms, X and Y scatter charts (X) are listed at the same time.
The following two sample graphs are typical bar graphs and line graphs, and the components are marked in red font.
Charts should tell readers as much information as possible, such as:
(1) The results reflected in the chart, including a brief statistical description;
(2) If possible, indicate the research object of the experiment;
(3) the conditional background of the results, such as the processing methods adopted or the relationship between the displays;
(4) experimental site (only needed for outdoor experiments);
(5) Detailed charts are needed to explain the results reflected by charts (many magazines emphasize that charts need to be an independent part, that is, readers can understand the results of papers without reading, which is often ignored by many China authors);
(6) If possible, indicate the parameters or conditions (temperature, medium, etc. ) culture or treatment;
(7) the sample size and statistical test results of the experiment;
(8) Don't simply repeat "pair" between the labels of two axes.
I. Structural composition
1. myth; legend
The title is usually located at the bottom of the table. Figure can be abbreviated as "Figure", which is arranged in Arabic numerals according to the order in which the numbers appear in the article (for example, for composite numbers, many numbers often share a title, but each number must be clearly marked with capital letters (A, B, C, etc.). ), and the title of the composite map must also distinguish each map, and when describing in the text, mark the data information reflected by it with letters.
For example:
2. Axis label
For statistical charts with horizontal axis and vertical axis, the two axes should have corresponding axes and indicate the units.
3. Counting axes
The scale of the number axis should be equidistant or have certain regularity (such as logarithmic scale), and the numerical value should be marked. The scale of the horizontal axis is from left to right, and the scale of the vertical axis is from bottom to top. Numerical values must start from "0" point (except logarithmic and bitmap).
4. Icons (symbols and symbol keys)
When different lines, images or colors are used to represent different things in the picture, icons should be used to explain them, and icons should be clear and easy to distinguish.
Second, the text citation (description)
In this paper, we must mention every number in the paper, and explain or summarize the relationship or trend of things reflected by statistics.
For example:
The germination rate after 24 hours in running water is obviously higher than that of the control (Figure 4).
Third, commonly used statistical charts
The usage of four commonly used statistical charts is listed below: bar chart, frequency histogram and XY scatter chart.
1. Bar chart
Bar chart is to use the length of the bar to represent the numerical value of each category of classified data, and to show the comparative relationship between them. Can be divided into single type and double type.
Simple bar chart:
(1) The title (Figure 1) is located at the bottom of the figure. The title is rich in information, including processing methods, statistical tests and significant level descriptions.
(2)y axis represents the measured value (stem length), and the unit is marked as (mm); The x-axis is different treatment groups.
(3) The error range is marked on each bar chart and explained in the title.
(4) Statistical differences between treatment groups are represented by horizontal lines on the error bars and explained in the title.