Duplicate Columns in Regression Summary Output Table

   Lower 95%     Upper 95%     Lower 95.0%     Upper 95.0%
        5             5               5               5
       -1            -1              -1              -1
				

MORE INFORMATION

In Microsoft Excel, you can use the Analysis ToolPak add-in to perform a variety of data analysis functions, including linear regression analysis. The following steps demonstrate the problem described earlier:

1. In Microsoft Excel, create a new workbook. In Sheet1, enter the following data:

   A1: 1 B1: 9
   A2: 2 B2: 8
   A3: 3 B3: 7
   A4: 4 B4: 6
   

2. On the Tools menu, click Data Analysis. Select Regression, and click OK.
3. In the Input Y Range edit box, type $A$1:$A$4.
4. In the Input X Range edit box, type $B$1:$B$4.
5. Click Output Range, and enter $D$1 in the edit box to the right of the option button.
6. Click OK.
   
   The Summary Output table appears in the worksheet, starting in cell D1. If you scroll down to cells I16:L18, you see the following data:

      Lower 95%     Upper 95%     Lower 95.0%     Upper 95.0%
           10            10              10              10
           -1            -1              -1              -1
   						

   Note that the first two columns display the lower and upper 95%, and that the last two columns also display the lower and upper 95.0%. This is true because the Confidence Level check box was not checked in the Regression dialog box.
7. On the Tools menu, click Data Analysis. Select Regression, and click OK.
8. Click to select the Confidence Level check box. Enter 85 in the edit box to the right of the check box.
9. Click OK. Click OK again to overwrite the existing table.

Note that the following appears in cells I16:L18:

   Lower 95%     Upper 95%     Lower 85.0%     Upper 85.0%
        10            10              10              10
        -1            -1              -1              -1
				

The first two columns still display the lower and upper 95%; the last two columns now display the lower and upper 85.0%.