Double-click the Excel workbook document in which your data is stored. If you don't have the data that you want to analyze in a spreadsheet yet, you'll instead open Excel and click Blank workbook to open a new workbook. You can then enter your data and create a graph from it. Click the graph to which you want to assign a trendline. If you haven't yet created a graph from your data, create one before continuing. It's a green button next to the upper-right corner of the graph. A drop-down menu will appear. You may need to hover your mouse over the far-right side of the "Trendline" box to prompt this arrow to appear. Clicking it brings up a second menu. Depending on your preferences, click one of the following options  Linear Exponential Linear Forecast Two Period Moving Average You can also click More Options... to bring up an advanced options panel after selecting data to analyze. Click a data series name (e.g., Series 1) in the pop-up window. If you named your data already, you'll click the data's name instead. It's at the bottom of the pop-up window. Doing so adds a trendline to your graph. If you clicked More Options... earlier, you'll have the option of naming your trendline or changing the trendline's persuasion on the right side of the window. Press Ctrl+S to save your changes. If you've never saved this document before, you'll be prompted to select a save location and file name.

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Write a summary of the previous text in Chinese:
打开Excel工作簿。 选择图形。 点击＋。 点击“趋势线”框右边的箭头。 选择一个趋势线选项。 选择要分析的数据。 点击OK。 保存工作。