A Guide to Microsofl Excel 2002 for Scientists and Engineers phần 5

Hình minh họa một công thức bằng cách sử dụng một chức năng. Hàm MAX trả về giá trị của đối số lớn nhất. Các công thức trong hình sẽ trở lại lớn hơn giá trị trong Al, một trong những giá trị trong phạm vi B1: B8 hoặc giá trị hằng số 10. Trong ví dụ này, các đối số là một tham chiếu di động, tài liệu tham khảo một phạm vi và một hằng số. | Curve Fitting 121 Insert Function tool Exercise 2 Adding the Trendline to a Chart b In J3 enter SLOPE B3 F3 B2 F2 . This will return the slope of the line of best fit for the data. Remember that in addition to simply typing this formula we can use the Insert Function dialog which may be called i using the Insert Function tool or ii by typing the start of the formula SLOPE and using CtrĩỊ-1-A to bring up the Function Argument dialog box. Note the syntax of the function is SLOPE Amớh w_ Yvalues known_x values . Take care to remember this since it seems backwards to most scientists and engineers who are accustomed to listing x-values before y-values. c In J4 enter INTERCEPT B3 F3 B2 F2 . This will return the value of the intercept of the line of best fit. The syntax is INTERCEPT Amớh w_ Yvalues known X values . d Save the workbook as . Knowing the m and b values for the best fit line ỹ mx b we could use the formula J 2 B2 J 3 in cell B4 and copy it to C4 F4. Alternatively we could use the TREND function to place they values for the best fit in B4 F4. We might then plot A2 F4 showing the experimental data B3 F3 with markers and no connecting line and the best fit data B4 F4 with a line and no markers. The reader is encouraged to experiment with both methods. But there is a quicker way as we will see in the next exercise. Microsoft Excel has a feature for plotting the line of best fit on an XY chart. This is called the trendline. In this exercise we will see how to add a trendline and how to extend it. In the subsequent exercise we will learn how to display on the chart the equation of this line of best fit. a On Sheetl of construct an XY chart of the data in the range B2 F3. In Step 1 of the Chart Wizard select the first XY subtype which shows the data plotted with markers but no joining line. b Right click on any marker and select Insert Trendline from the resulting menu. A dialog box is opened - see Figure . Select the thumbnail sketch of a .