How to draw a full picture of a standard curve in Excel

 

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With the increasing popularity of computers, more and more testers hope to get rid of some tedious work, such as drawing standard curves, quality control charts, and calculating detection values. Of course, using the office system of the laboratory is theoretically the most convenient, but many organizations do not have the office system of the laboratory. In fact, the use of Microsoft Excel spreadsheet tools will also bring great convenience to the inspection work.

Excel is an important component of Microsoft offices system. It is a workbook tool between word processing software and Access database software. It has powerful functions and is especially suitable for daily work. It is better than the existing Office System in the laboratory.

This section describes how to use Excel to draw a standard curve.

First, complete the data input in Excel, select the completed data area, and click the chart wizard, as shown in.

Click the chart wizard to run the chart wizard, for example, select "XY scatter chart" in the chart type, and select "scatter chart" in the chart type (the first unconnected ).

Click "Next". The page is displayed. If the input is the horizontal list of this example, you do not need to change it. If the input is a vertical list, you can select "column ".

If you find that the image is not ideal, you should carefully check whether there is a problem with the data zone selection. If there is an error, you can click "series" to change it, as shown in.

If the value of X is incorrect, click the small icon on the right of the text box. The result is as follows:

Select the correct data area on the table. Click "Next" to display the chart Options page. For example, you should adjust the options to meet your needs.

Click "Next". Now a complete scatter chart with the standard value is complete, as shown in.

After completing the scatter chart, we need to perform regression analysis based on the data, calculate the regression equation, and draw a standard curve. In fact, this is very simple. First, click the standard value on the graph, right-click it, and click "add trend line ". For example.

Because this example is a linear relationship, select "linear" in the type as shown in Figure

Click "OK" to return to the standard curve and draw a picture.

The standard curve is drawn, but how do we know what the regression equation is like? This is simple. Right-click the trend line (that is, the standard curve we call) and select the trend line format, such:

Before the formula is displayed and the R square value (linear correlation coefficient) is displayed, click it. Click OK. Now, the formula and correlation coefficient are all available. H. R has a level of 0.996, and the linearity is quite good.

However, sometimes some projects increase exponentially. scatter plots are shown in the following figure,

From the perspective of it, there is no value off, except for the biggest point, and almost all the other points have become straight lines. This is not hard to understand. For 10000000, 10 and 10000 are not much different. Therefore, we usually use semi-log copy to draw images. For excel, click Y axis, right-click it, and select "axis format", as shown in

Select the logarithm scale in the lower left and click OK. A complete standard semi-logarithm curve is ready.

Is it easy to create a standard curve using Excel? If you adjust the parameters carefully, you can get different results.

Some people say that the standard curve is used. If we can input the signal value, we can get the concentration. In fact, we can use Excel to process it freely. For details, refer to the next decomposition.