# Creating a Weibull Plot in Microsoft® Excel

## Chapter 5, Example 16

1. Launch Excel.

2. Enter the data and calculations

• In cell A1, type "i"

• In cell B1, type "xi"

• In cell C1, type "ln(xi)"

• In cell D1, type "p"

• In cell E1, type "ln(-ln(1-p))"

• In cells A2-A21, enter the integers 1-20.

• In cells B2-B21, enter the insulation failure voltage data from Figure 5.24 (p. 275).

• In cell C2, type "=ln(B2)"

• Select cells C2-C21; then select "Edit --> Fill --> Down."

Excel fills Column C with the natural log of the values in Column B, as shown in Table 5.9 (p. 276).

• In cell D2, type "=(A2-0.5)/20"

• Select cells D2-D21; then select "Edit --> Fill --> Down."

Excel fills Column D with the formula (i-.5)/20, as shown in Table 5.9.

• In cell E2, type "=ln(-ln(1-D2))"

• Select cells E2-E21; then select "Edit --> Fill --> Down."

Excel fills Column E with the formula (ln(-ln(1-p)), as shown in Table 5.9.

Screenshot:

3. Plot ln(-ln(1-p)) vs. ln(xi).

• Select "Insert --> Chart."

• In the dialog box that follows, select "XY (Scatter)" from the list labeled "Chart Type. Under "Chart sub-type," select the first option (no lines).

Screenshot:

• Click "Next."

• Fill out the "Data Range" panel of the resulting dialog box as follows:

Input Type Label Value
Data Range: =Sheet1!\$C\$2:\$C\$21,Sheet1!\$E\$2:\$E\$21
Columns selected

Screenshot:

• Click "Next."

• Fill out the "Titles" pane of the resulting dialog box as follows:

Input Type Label Value
Chart title: Weibull Plot for Insulation Failure Voltage
Value (X) axis: ln(failure voltage)
Value (Y) axis: ln(-ln(1-p))

Screenshot:

• Click "Next."

• Fill out the resulting dialog box as follows:

Input Type Label Value
As object in: selected
As object in: Sheet1

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• Click "Finish."

Excel plots ln(-ln(1-p)) vs. ln(failure voltage) and inserts the chart into Sheet1.

Screenshot:

Note: you can resize the chart that contains the plot by clicking a blank area in the chart to select it and dragging one of the handles that appears on the chart's border. You can further modify the chart by double-clicking various chart elements.