Note: The first seven options (Show Points, Show Kaplan Meier, Show Combined, Show Confid Interval, Show Simultaneous CI, Show Shaded Pointwise CI, and Show Shaded Simultaneous CI) and the last two options (Fitted Survival CI, Fitted Failure CI) pertain to the initial survival plot and failure plot. The other five (Midstep Quantile Points, Connect Quantile Points, Fitted Quantile, Fitted Quantile CI Lines, Fitted Quantile CI Shaded) pertain only to the distributional plots.
Show Points shows the sample points at each step of the survival plot. Failures appear at the bottom of the steps, and censorings are indicated by points above the steps.
Show Kaplan Meier shows the Kaplan-Meier curves. This option is on by default.
Show Combined shows the survival curve for the combined groups in the Survival Plot.
Show Confid Interval shows the pointwise 95% confidence bands on the survival plot for groups and for the combined plot when it appears with the Show Combined option.
When you select Show Points and Show Combined, the survival plot for the total or combined sample appears as a gray line. The points also appear at the plot steps of each group.
Show Simultaneous CI shows the simultaneous confidence bands for all groups on the plot. Meeker and Escobar (1998, chap. 3) discuss pointwise and simultaneous confidence intervals and the motivation for simultaneous confidence intervals in survival analysis.
Midstep Quantile Points changes the plotting positions to use the modified Kaplan-Meier plotting positions, which are equivalent to taking mid-step positions of the Kaplan-Meier curve, rather than the bottom-of-step positions. This option is recommended, so it is on by default.
Connect Quantile Points shows the lines in the plot. This option is on by default.
Fitted Quantile shows the straight-line fit on the fitted Weibull, lognormal, or exponential plot. This option is on by default.
Fitted Quantile CI Lines shows the 95% confidence bands for the fitted Weibull, lognormal, or exponential plot.
Fitted Quantile CI Shaded shows the display of the 95% confidence bands for a fit as a shaded area or dashed lines.
Fitted Survival CI shows the confidence intervals (on the survival plot) of the fitted distribution.
Fitted Failure CI shows the confidence intervals (on the failure plot) of the fitted distribution.
Exponential, Weibull, and Lognormal Plots and Reports
The Weibull distribution is the most popular for event-time data. There are many ways in which different authors parameterize this distribution (as shown in Various Weibull Parameters in Terms of JMP’s alpha and beta). JMP reports two parameterizations, labeled the lambda-delta extreme value parameterization and the Weibull alpha-beta parameterization. The alpha-beta parameterization is used in the reliability literature. See Nelson (1990). Alpha is interpreted as the quantile at which 63.2% of the units fail. Beta is interpreted as follows: if beta>1, the hazard rate increases with time; if beta<1, the hazard rate decreases with time; and if beta=1, the hazard rate is constant, meaning it is the exponential distribution.
Confidence Contour Plot
Fitted Distribution Plots for Three Distributions
These plots can be transferred to other graphs through the use of graphic scripts. To copy the graph, right-click in the plot to be copied and select Edit > Copy Frame Contents. Right-click in the destination plot and select Edit > Paste Frame Contents.
alpha=alpha
beta=beta
eta=alpha
beta=beta
c = alpha
m = beta
eta=alpha
beta=beta
beta=alpha
alpha=beta
p = beta
mu=log(alpha)
Adds a new column to the current table called log(–log(Surv)). This information is often used to plot against the time variable with a grouping variable, such as the code for type of failure.