SurvivalDistribution
✖
SurvivalDistribution
represents a survival distribution where events ei occur with censor weights cwi.
Details and Options


- SurvivalDistribution is used in survival, reliability, and duration analysis.
- SurvivalDistribution produces a DataDistribution object representing the EmpiricalDistribution of censored lifetime data.
- The following individual event specifications can be used for ei:
-
ti no censoring; event happens at tti {ti,∞} right censoring; event happens at some t where ti≤t {-∞,ti} left censoring; event happens at some t where t<ti {ti,min,ti,max} interval censoring; event happens at some t where ti,min<t≤ti,max - The following individual censor weight specifications can be used for cwi:
-
ci ci events at ei {ci,ri} ci events and ri right-censored events at ei {ci,ri,li} ci events, ri right-censored, and li left-censored events at ei - In SurvivalDistribution, the lists of event times and weights must be the same length.
- EventData[{t1,…},{i1,…}] can be used to transform event times {t1,…} with censoring vector {i1,…} to the form {{t1,min,t1,max},…}.
- The following options can be given:
-
Method Automatic method to use WorkingPrecision Automatic precision to use in internal computations - SurvivalDistribution automatically chooses the method most appropriate to the data. The Kaplan–Meier estimator is used for right-censored data. For other types of censoring, the estimate is constructed using a self-consistency approach. Different methods may only support some types of censoring.
- Possible settings for Method include:
-
Automatic automatically select the most appropriate method "Turnbull" Turnbull algorithm for interval-censored data "KaplanMeier" product limit estimator for right-censored data "NelsonAalen" based on the Nelson–Aalen cumulative hazard estimator "Noncensored" censoring is ignored and interval midpoints are used "SelfConsistency" Turnbull algorithm for doubly censored data - SurvivalDistribution can be used with such functions as Mean, CDF, and RandomVariate.
Examples
open allclose allBasic Examples (1)Summary of the most common use cases
Create a survival distribution from some right-censored survival data:

https://wolfram.com/xid/04z1r6qkfq819dwa-7els8w

https://wolfram.com/xid/04z1r6qkfq819dwa-bhw5pd

https://wolfram.com/xid/04z1r6qkfq819dwa-hs8w3i
Visualize the survival function:

https://wolfram.com/xid/04z1r6qkfq819dwa-bjqg3p

Compute moments and quantiles:

https://wolfram.com/xid/04z1r6qkfq819dwa-dhwfvv


https://wolfram.com/xid/04z1r6qkfq819dwa-c96hbo

Scope (24)Survey of the scope of standard use cases
Basic Uses (4)
Create an empirical model for some right-censored survival data:

https://wolfram.com/xid/04z1r6qkfq819dwa-i95f1b

https://wolfram.com/xid/04z1r6qkfq819dwa-fbnlo3
Use like any other distribution:

https://wolfram.com/xid/04z1r6qkfq819dwa-be1ewx


https://wolfram.com/xid/04z1r6qkfq819dwa-dxeln3

Compute probabilities and expectations:

https://wolfram.com/xid/04z1r6qkfq819dwa-dxfpu


https://wolfram.com/xid/04z1r6qkfq819dwa-glv2hf

Create a nonparametric maximum likelihood estimate for doubly censored data:

https://wolfram.com/xid/04z1r6qkfq819dwa-gliork
Use EventData to convert status indicators:

https://wolfram.com/xid/04z1r6qkfq819dwa-hc9nv


https://wolfram.com/xid/04z1r6qkfq819dwa-bbv2lp
Visualize the survival and cumulative hazard functions:

https://wolfram.com/xid/04z1r6qkfq819dwa-mzzl6y

Estimate the distribution for interval-censored data:

https://wolfram.com/xid/04z1r6qkfq819dwa-gcducz

https://wolfram.com/xid/04z1r6qkfq819dwa-b83q90
The empirical distribution function:

https://wolfram.com/xid/04z1r6qkfq819dwa-e6gi5j


https://wolfram.com/xid/04z1r6qkfq819dwa-ce2wde

Specify weights to easily input frequency data:

https://wolfram.com/xid/04z1r6qkfq819dwa-c5n5xk
These weights indicate double censoring:

https://wolfram.com/xid/04z1r6qkfq819dwa-4hwx

https://wolfram.com/xid/04z1r6qkfq819dwa-e6oj4o
The estimated survival function:

https://wolfram.com/xid/04z1r6qkfq819dwa-c0j52

Distribution Properties (5)
Estimate distribution functions:

https://wolfram.com/xid/04z1r6qkfq819dwa-mlunew
The PDF and hazard function are discrete:

https://wolfram.com/xid/04z1r6qkfq819dwa-chlfq0

The CDF and survival function are piecewise constant:

https://wolfram.com/xid/04z1r6qkfq819dwa-e5g0hs

Compute moments of the distribution:

https://wolfram.com/xid/04z1r6qkfq819dwa-i5ffi7

https://wolfram.com/xid/04z1r6qkfq819dwa-cfzros


https://wolfram.com/xid/04z1r6qkfq819dwa-mb96ea


https://wolfram.com/xid/04z1r6qkfq819dwa-ebrr47


https://wolfram.com/xid/04z1r6qkfq819dwa-kgpegz


https://wolfram.com/xid/04z1r6qkfq819dwa-447p5


https://wolfram.com/xid/04z1r6qkfq819dwa-rtnii

https://wolfram.com/xid/04z1r6qkfq819dwa-brbub2


https://wolfram.com/xid/04z1r6qkfq819dwa-d7yzze


https://wolfram.com/xid/04z1r6qkfq819dwa-c5pl1i


https://wolfram.com/xid/04z1r6qkfq819dwa-ou6pnr


https://wolfram.com/xid/04z1r6qkfq819dwa-dcazg5


https://wolfram.com/xid/04z1r6qkfq819dwa-emcwmm

https://wolfram.com/xid/04z1r6qkfq819dwa-jwtz4z

Only values in the distribution domain are possible:

https://wolfram.com/xid/04z1r6qkfq819dwa-ghjk26

Compute probabilities and expectations:

https://wolfram.com/xid/04z1r6qkfq819dwa-b7zjch

https://wolfram.com/xid/04z1r6qkfq819dwa-e1qaka


https://wolfram.com/xid/04z1r6qkfq819dwa-bh3dm4

Censoring (7)
Uncensored data can be represented on intervals (no censoring):

https://wolfram.com/xid/04z1r6qkfq819dwa-clk19c

https://wolfram.com/xid/04z1r6qkfq819dwa-bh48vc
The survival functions are equivalent:

https://wolfram.com/xid/04z1r6qkfq819dwa-guijzy

Estimate the distribution with right-censored data (right censoring):

https://wolfram.com/xid/04z1r6qkfq819dwa-bwj0mt

https://wolfram.com/xid/04z1r6qkfq819dwa-vt6k1
The jump at 16 has been removed and the survival function has been rescaled beyond 16:

https://wolfram.com/xid/04z1r6qkfq819dwa-ek8oor

A single left-censored observation (left censoring):

https://wolfram.com/xid/04z1r6qkfq819dwa-jvy0px

https://wolfram.com/xid/04z1r6qkfq819dwa-gg90f3
The jump at 16 is removed and the probability is redistributed over the estimate:

https://wolfram.com/xid/04z1r6qkfq819dwa-b9xg88

Observations can be censored on an interval (interval censoring):

https://wolfram.com/xid/04z1r6qkfq819dwa-bqm14o
The third observation occurred somewhere on the interval :

https://wolfram.com/xid/04z1r6qkfq819dwa-h62tn

https://wolfram.com/xid/04z1r6qkfq819dwa-czea2e

Any combination of left- and right-censored observations is possible (double censoring):

https://wolfram.com/xid/04z1r6qkfq819dwa-ntpfi
The second observation is left censored and the fourth is right censored:

https://wolfram.com/xid/04z1r6qkfq819dwa-gwxrq3

https://wolfram.com/xid/04z1r6qkfq819dwa-c9i4eq

Any type of censoring can be present in the data simultaneously (mixed censoring):

https://wolfram.com/xid/04z1r6qkfq819dwa-b4zvne
The second, third, and fourth observations are left, interval, and right censored, respectively:

https://wolfram.com/xid/04z1r6qkfq819dwa-z6ukn

https://wolfram.com/xid/04z1r6qkfq819dwa-fbkbie

Use EventData with status indicators to indicate censored observations:

https://wolfram.com/xid/04z1r6qkfq819dwa-fjynyz

https://wolfram.com/xid/04z1r6qkfq819dwa-gqwszk
Create distributions for the different censoring schemes:

https://wolfram.com/xid/04z1r6qkfq819dwa-w1zoz

https://wolfram.com/xid/04z1r6qkfq819dwa-mbexsx

Truncation (2)
Use EventData to specify truncated observations:

https://wolfram.com/xid/04z1r6qkfq819dwa-gbk1j

https://wolfram.com/xid/04z1r6qkfq819dwa-ckhrky

https://wolfram.com/xid/04z1r6qkfq819dwa-p6q6ml

https://wolfram.com/xid/04z1r6qkfq819dwa-eva3ob

EventData can be used to mix censoring and truncation:

https://wolfram.com/xid/04z1r6qkfq819dwa-kso4l4

https://wolfram.com/xid/04z1r6qkfq819dwa-it0kl
The survival function for some left-truncated and right-censored data:

https://wolfram.com/xid/04z1r6qkfq819dwa-lgpxt

Censor Weights (6)
Provide a list of observation censor weights:

https://wolfram.com/xid/04z1r6qkfq819dwa-c2e0ek

https://wolfram.com/xid/04z1r6qkfq819dwa-cp2tq2
The second value was observed twice, causing a greater decline in the survival function at 15:

https://wolfram.com/xid/04z1r6qkfq819dwa-bb89cz

Specify right censoring with a list of censor weights:

https://wolfram.com/xid/04z1r6qkfq819dwa-f57nw5

https://wolfram.com/xid/04z1r6qkfq819dwa-yqjls
There was one right-censored observation at 15:

https://wolfram.com/xid/04z1r6qkfq819dwa-kbdqyy

Left-censored observations can also be specified in a list of censor weights:

https://wolfram.com/xid/04z1r6qkfq819dwa-ikydgi

https://wolfram.com/xid/04z1r6qkfq819dwa-bkahh1
There were three left-censored observations at 15:

https://wolfram.com/xid/04z1r6qkfq819dwa-ifdkb6

Uncensored, right-censored, and left-censored observations can be specified simultaneously:

https://wolfram.com/xid/04z1r6qkfq819dwa-5h0x4

https://wolfram.com/xid/04z1r6qkfq819dwa-bjhpyj
There were two uncensored, one right-censored, and three left-censored observations at 15:

https://wolfram.com/xid/04z1r6qkfq819dwa-jhbwvt

The censor weight list can be used with interval-censored observations:

https://wolfram.com/xid/04z1r6qkfq819dwa-bnhi1y

https://wolfram.com/xid/04z1r6qkfq819dwa-cb7b9y
The second observation is interval censored and occurred twice:

https://wolfram.com/xid/04z1r6qkfq819dwa-fwyxm0

The censor weight list can be used to drop unwanted observations:

https://wolfram.com/xid/04z1r6qkfq819dwa-dyyd6i

https://wolfram.com/xid/04z1r6qkfq819dwa-kv8h9x
The second observation was dropped:

https://wolfram.com/xid/04z1r6qkfq819dwa-ns0qwm

Options (6)Common values & functionality for each option
Method (5)
By default, the method used is based on the types of censoring present in the data:

https://wolfram.com/xid/04z1r6qkfq819dwa-ckywq0

https://wolfram.com/xid/04z1r6qkfq819dwa-cjusv2

https://wolfram.com/xid/04z1r6qkfq819dwa-m6u9zp


https://wolfram.com/xid/04z1r6qkfq819dwa-fs21qd

https://wolfram.com/xid/04z1r6qkfq819dwa-b7aw73

https://wolfram.com/xid/04z1r6qkfq819dwa-eejr0


https://wolfram.com/xid/04z1r6qkfq819dwa-l303g7

https://wolfram.com/xid/04z1r6qkfq819dwa-dt37p2

https://wolfram.com/xid/04z1r6qkfq819dwa-k8i39t


https://wolfram.com/xid/04z1r6qkfq819dwa-gqp5p0

https://wolfram.com/xid/04z1r6qkfq819dwa-wegrr

https://wolfram.com/xid/04z1r6qkfq819dwa-c2qosr

Set the maximum number of iterations for iterative algorithms:

https://wolfram.com/xid/04z1r6qkfq819dwa-dt2gr6

https://wolfram.com/xid/04z1r6qkfq819dwa-ft59y1

https://wolfram.com/xid/04z1r6qkfq819dwa-boe4kc

The default maximum number of iterations is 10000:

https://wolfram.com/xid/04z1r6qkfq819dwa-bdsfn

https://wolfram.com/xid/04z1r6qkfq819dwa-hkuk54

https://wolfram.com/xid/04z1r6qkfq819dwa-4zxg2

Iterations are not necessary in the absence of left or interval censoring:

https://wolfram.com/xid/04z1r6qkfq819dwa-etu7iu

https://wolfram.com/xid/04z1r6qkfq819dwa-de2cn3
The algorithm converges immediately:

https://wolfram.com/xid/04z1r6qkfq819dwa-xm0dj

Control convergence of Turnbull algorithms:

https://wolfram.com/xid/04z1r6qkfq819dwa-eb3lx

https://wolfram.com/xid/04z1r6qkfq819dwa-gbg9mn
Mean estimates with increasing PrecisionGoal:

https://wolfram.com/xid/04z1r6qkfq819dwa-f8j10f

WorkingPrecision (1)
Estimate the SurvivalFunction using 30-digit-precision arithmetic:

https://wolfram.com/xid/04z1r6qkfq819dwa-i49to

https://wolfram.com/xid/04z1r6qkfq819dwa-epr9f

https://wolfram.com/xid/04z1r6qkfq819dwa-bj5cpi

Applications (7)Sample problems that can be solved with this function
Compare the survival rates of breast cancer patients with different immuno-histochemical responses, given the following data and that follow-up times were 116 and 87 weeks for groups one and two, respectively:

https://wolfram.com/xid/04z1r6qkfq819dwa-klip7

https://wolfram.com/xid/04z1r6qkfq819dwa-jbve7l
Estimate the distributions of each group:

https://wolfram.com/xid/04z1r6qkfq819dwa-iaaqvw
Visually compare the survival functions:

https://wolfram.com/xid/04z1r6qkfq819dwa-ed74u6

Find the average number of weeks a breast cancer patient survives in the two groups:

https://wolfram.com/xid/04z1r6qkfq819dwa-g365bi

Ignoring censoring causes an underestimate in the survival function:

https://wolfram.com/xid/04z1r6qkfq819dwa-drnwj2

A group of 191 high-school boys was asked the exact age at which they started using marijuana. Responses were "I used it first at age ", "I never used it", and "I have used it but cannot recall when the first time was". Estimate the survival function for time to first marijuana use given the following data:

https://wolfram.com/xid/04z1r6qkfq819dwa-fh3jvc

https://wolfram.com/xid/04z1r6qkfq819dwa-kkfge
The probability of a person not having used marijuana at a certain age:

https://wolfram.com/xid/04z1r6qkfq819dwa-mcg6cm

https://wolfram.com/xid/04z1r6qkfq819dwa-f5ddo

Find the probability of a person having used marijuana at age 15 or earlier:

https://wolfram.com/xid/04z1r6qkfq819dwa-nzn6s0

Estimate the survival of children with acute leukemia treated with the drug 6-mercaptopurine using the Nelson–Aalen and Kaplan–Meier estimators:

https://wolfram.com/xid/04z1r6qkfq819dwa-h3d9x6

https://wolfram.com/xid/04z1r6qkfq819dwa-c5opiq
The estimates are quite similar:

https://wolfram.com/xid/04z1r6qkfq819dwa-b3v3jf

Plot the Nelson–Aalen estimate of the cumulative hazard function:

https://wolfram.com/xid/04z1r6qkfq819dwa-3sb5l

Compare survival curves for patients with acute myelogenous leukemia given extended maintenance of chemotherapy (M) versus non-maintained (NM) chemotherapy using the following data:

https://wolfram.com/xid/04z1r6qkfq819dwa-l5hsgh

https://wolfram.com/xid/04z1r6qkfq819dwa-qcpa2

https://wolfram.com/xid/04z1r6qkfq819dwa-hmrcw5
Show markers at the occurrence of censored observations:

https://wolfram.com/xid/04z1r6qkfq819dwa-lt48s1
It appears that survival is longer when chemotherapy is maintained:

https://wolfram.com/xid/04z1r6qkfq819dwa-b6gkxh

Estimate the cumulative hazard function for time to retraction for breast cancer patients treated by radiotherapy given the following data:

https://wolfram.com/xid/04z1r6qkfq819dwa-huf47

https://wolfram.com/xid/04z1r6qkfq819dwa-jjestl
Show the resulting cumulative hazard function:

https://wolfram.com/xid/04z1r6qkfq819dwa-hxqr01

Compute the expected time to retraction given the absence of retraction by week 20:

https://wolfram.com/xid/04z1r6qkfq819dwa-g0nczn

A set of manufactured cords was placed under stress until breakage. Some of the cords were damaged in some way during the study and so their true reliability is right censored. Given the data, estimate the reliability function:

https://wolfram.com/xid/04z1r6qkfq819dwa-o2lnq

https://wolfram.com/xid/04z1r6qkfq819dwa-mf5otc
The reliability function is the probability a cord will hold beyond a particular stress:

https://wolfram.com/xid/04z1r6qkfq819dwa-g1gged

https://wolfram.com/xid/04z1r6qkfq819dwa-5wq17

Determine the expected breaking point, given a cord has not broken at 45 lbs of stress:

https://wolfram.com/xid/04z1r6qkfq819dwa-cyfni6

The break-point data for 17 ropes is given where the maximum stress applied was 100 lbs of force. Compare the empirical estimate to a Weibull model:

https://wolfram.com/xid/04z1r6qkfq819dwa-ctpryj

https://wolfram.com/xid/04z1r6qkfq819dwa-f676u
Model the survival function with a censored Weibull distribution:

https://wolfram.com/xid/04z1r6qkfq819dwa-cmo18r
An empirical model using SurvivalDistribution:

https://wolfram.com/xid/04z1r6qkfq819dwa-b3s6kf

https://wolfram.com/xid/04z1r6qkfq819dwa-jyqmab

Compute the probability a rope will break beyond 60 lbs of force using the two models:

https://wolfram.com/xid/04z1r6qkfq819dwa-oy97c


https://wolfram.com/xid/04z1r6qkfq819dwa-d1pemm

Properties & Relations (9)Properties of the function, and connections to other functions
Probabilities for each observation are distributed in the direction of censoring:

https://wolfram.com/xid/04z1r6qkfq819dwa-n7sdn
The impact of adding three observations each for three censoring types:

https://wolfram.com/xid/04z1r6qkfq819dwa-bixixb

Right-censored observations are truncated at the largest finite endpoint:

https://wolfram.com/xid/04z1r6qkfq819dwa-ehaka0

https://wolfram.com/xid/04z1r6qkfq819dwa-m5iba

https://wolfram.com/xid/04z1r6qkfq819dwa-rfrx7

If the last observation is right censored, the distribution is truncated:

https://wolfram.com/xid/04z1r6qkfq819dwa-el425i

https://wolfram.com/xid/04z1r6qkfq819dwa-bfl974
The survival function is truncated at the last finite endpoint at 25:

https://wolfram.com/xid/04z1r6qkfq819dwa-dalu6a

This endpoint can be set arbitrarily, using a list of weights:

https://wolfram.com/xid/04z1r6qkfq819dwa-k1b0u
The value 30 was added to the domain of the distribution without adding any observations:

https://wolfram.com/xid/04z1r6qkfq819dwa-eklch2

https://wolfram.com/xid/04z1r6qkfq819dwa-hl2szc

Agreement with the uncensored case diverges with an increased proportion of censoring:

https://wolfram.com/xid/04z1r6qkfq819dwa-cfi33l

https://wolfram.com/xid/04z1r6qkfq819dwa-c9ddqs

https://wolfram.com/xid/04z1r6qkfq819dwa-bf6eyn

The PDF and hazard function are discrete:

https://wolfram.com/xid/04z1r6qkfq819dwa-blfipd

https://wolfram.com/xid/04z1r6qkfq819dwa-csp35a

https://wolfram.com/xid/04z1r6qkfq819dwa-gfeba

For comparison to continuous distributions, the cumulative hazard function can be used:

https://wolfram.com/xid/04z1r6qkfq819dwa-bonzka

https://wolfram.com/xid/04z1r6qkfq819dwa-jl7om

CensoredDistribution applies censoring to a distribution, not individual observations:

https://wolfram.com/xid/04z1r6qkfq819dwa-dh2a6j

https://wolfram.com/xid/04z1r6qkfq819dwa-eca36q

https://wolfram.com/xid/04z1r6qkfq819dwa-fm848o
Treat all observations outside of the window as right censored:

https://wolfram.com/xid/04z1r6qkfq819dwa-dqoya2

Using Clip on data is equivalent to CensoredDistribution over the same window:

https://wolfram.com/xid/04z1r6qkfq819dwa-h20zae

https://wolfram.com/xid/04z1r6qkfq819dwa-do5tbp

https://wolfram.com/xid/04z1r6qkfq819dwa-d0tajy

https://wolfram.com/xid/04z1r6qkfq819dwa-lqxoc

With no censoring, SurvivalDistribution is equivalent to EmpiricalDistribution:

https://wolfram.com/xid/04z1r6qkfq819dwa-dwtg1

https://wolfram.com/xid/04z1r6qkfq819dwa-cep5d9

https://wolfram.com/xid/04z1r6qkfq819dwa-lp07i5

Using SurvivalDistribution with TruncatedDistribution is not equivalent to applying truncation to the data if censoring is present:

https://wolfram.com/xid/04z1r6qkfq819dwa-mpb72m

https://wolfram.com/xid/04z1r6qkfq819dwa-e21dt8

https://wolfram.com/xid/04z1r6qkfq819dwa-f44d6

https://wolfram.com/xid/04z1r6qkfq819dwa-iuqp9

https://wolfram.com/xid/04z1r6qkfq819dwa-e96sg6

https://wolfram.com/xid/04z1r6qkfq819dwa-21hgx

In the absence of censoring, these are equivalent:

https://wolfram.com/xid/04z1r6qkfq819dwa-foo0sk

https://wolfram.com/xid/04z1r6qkfq819dwa-cvo6ol

https://wolfram.com/xid/04z1r6qkfq819dwa-jvpbzj

Possible Issues (5)Common pitfalls and unexpected behavior
The weight list takes precedence over event specifications:

https://wolfram.com/xid/04z1r6qkfq819dwa-bdgl1q

https://wolfram.com/xid/04z1r6qkfq819dwa-fcpuc3


The weight list causes observations at to be added while dropping
:

https://wolfram.com/xid/04z1r6qkfq819dwa-cqavit

Unspecified positions in the weight list are assumed to be zero:

https://wolfram.com/xid/04z1r6qkfq819dwa-v3770

https://wolfram.com/xid/04z1r6qkfq819dwa-ce13zb

The left-censored observation was dropped. Place a value in the third position to avoid this:

https://wolfram.com/xid/04z1r6qkfq819dwa-1bzdt

https://wolfram.com/xid/04z1r6qkfq819dwa-g4pui0

The weight list can drop data from the analysis but not from the distribution domain:

https://wolfram.com/xid/04z1r6qkfq819dwa-co0r7v

https://wolfram.com/xid/04z1r6qkfq819dwa-kwg9go
The value at 30 was dropped from the analysis:

https://wolfram.com/xid/04z1r6qkfq819dwa-b654ar

The distribution domain was unaffected:

https://wolfram.com/xid/04z1r6qkfq819dwa-dh2n5l


https://wolfram.com/xid/04z1r6qkfq819dwa-egcb4f

Decreasing MaxIterations may result in failed convergence:

https://wolfram.com/xid/04z1r6qkfq819dwa-gvw2s3
Try increasing MaxIterations to avoid this:

https://wolfram.com/xid/04z1r6qkfq819dwa-b1oey5


https://wolfram.com/xid/04z1r6qkfq819dwa-bpdcjb

Setting the Method option may cause SurvivalDistribution to ignore features of the data:

https://wolfram.com/xid/04z1r6qkfq819dwa-l8wetx

https://wolfram.com/xid/04z1r6qkfq819dwa-cn92se
A warning is issued when features are ignored:

https://wolfram.com/xid/04z1r6qkfq819dwa-1gxyz




Finite endpoints and interval midpoints are treated as known event times using the "Noncensored" method:

https://wolfram.com/xid/04z1r6qkfq819dwa-cz4w3x

Interval midpoints and right endpoints in left-censored observations are treated as known for "KaplanMeier" or "NelsonAalen" methods:

https://wolfram.com/xid/04z1r6qkfq819dwa-isdm9q

The midpoints of intervals are treated as known using the "SelfConsistency" method:

https://wolfram.com/xid/04z1r6qkfq819dwa-nkn6j

Wolfram Research (2010), SurvivalDistribution, Wolfram Language function, https://reference.wolfram.com/language/ref/SurvivalDistribution.html.
Text
Wolfram Research (2010), SurvivalDistribution, Wolfram Language function, https://reference.wolfram.com/language/ref/SurvivalDistribution.html.
Wolfram Research (2010), SurvivalDistribution, Wolfram Language function, https://reference.wolfram.com/language/ref/SurvivalDistribution.html.
CMS
Wolfram Language. 2010. "SurvivalDistribution." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/SurvivalDistribution.html.
Wolfram Language. 2010. "SurvivalDistribution." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/SurvivalDistribution.html.
APA
Wolfram Language. (2010). SurvivalDistribution. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/SurvivalDistribution.html
Wolfram Language. (2010). SurvivalDistribution. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/SurvivalDistribution.html
BibTeX
@misc{reference.wolfram_2025_survivaldistribution, author="Wolfram Research", title="{SurvivalDistribution}", year="2010", howpublished="\url{https://reference.wolfram.com/language/ref/SurvivalDistribution.html}", note=[Accessed: 25-March-2025
]}
BibLaTeX
@online{reference.wolfram_2025_survivaldistribution, organization={Wolfram Research}, title={SurvivalDistribution}, year={2010}, url={https://reference.wolfram.com/language/ref/SurvivalDistribution.html}, note=[Accessed: 25-March-2025
]}