The “Input” tab shown in Figure 8-63 contains the fields specifying the data to be used for the Kaplan Meier Estimates. The time column contains the times or dates at which the subjects died or were censored. If any of the subjects were censored, the Permit censorship checkbox is checked and the Censor column contained the censorship marks. Censorship marks are typically 0s or 1s. The range of censor marks or labels can be set using the the remaining two spinboxes.
If the subjects belong to several groups and the groups are supposed to be analyzed separately, the groups tab can be used.
The groups tab can be enabled via the Define multiple groups checkbox. The groups column entry contains the address of the column specifying the group membership. Groups can then be defined or deleted via the Add and Remove buttons.
The options tab of the Kaplan-Meier tools dialog is used to set various options of the Kaplan-Meier tool.
The Output tab contains the standard output options and fields described in Section 8.1 ― Overview.
Suppose you want to calculate Kaplan-Meier Estimates for the as given in Figure 8-66. Each row contains the data for one subject. Column A contains the survival time, i.e. the time until death or censure. Column B contains the group number, we are considering two groups of subjects. Column C indicates whether the subject died (0) or was censured (1).
We complete the fields of the Input tab as shown in Figure 8-66. The time column is A2:A21 and the censure column is C2:C21.
Since we have two groups of subjects, on the Groups tab we check the Define multiple groups check box and set up two groups with identifiers 1 and 2 in column B2:B21:
On the Options tab all checkboxes are pre-checked and we leave them that way to obtain a maximum amount of information.
On the output tab we choose where we would like the output to be placed. For the purposes of this example we retain the New Sheet target. After clicking OK we get the output shown in Figure 8-68. Note that the graph initially always appears on top of the numerical result and was moved for the screen shot.
B1:F17 shows the results of the first group, G1 to K17 the results of the second group. The graph shows the Kaplan-Meier survival curves for both groups.
M4:N7 shows the result of the Mantel-Haenszel Log-Rank Test. In this case the p-value is larger than 0.3 and we would fail to reject the Null hypothesis. There is no evidence that the survival times differ.