---
title: A Closer Look at Probability and Survival Plots
description: A Closer Look at Probability and Survival Plots
image: https://blog.minitab.com/hubfs/B2BML%20-%20NEW%20FILE%20MANAGER%20STRUCTURE/Blog%20Images/Imported_Blog_Media/pic1-13-Jul-06-2025-12-20-55-3366-AM.png
---
English
- [English](https://blog.minitab.com/en/?hsLang=en)
- [Français](https://blog.minitab.com/fr/?hsLang=en)
- [Deutsch](https://blog.minitab.com/de/?hsLang=en)
- [Português](https://blog.minitab.com/pt/?hsLang=en)
- [Español](https://blog.minitab.com/es/?hsLang=en)
- [日本語](https://blog.minitab.com/ja/?hsLang=en)
- [한국어](https://blog.minitab.com/ko/?hsLang=en)
- [中文（简体）](https://blog.minitab.com/zh/?hsLang=en)
- [ Partners](https://www.minitab.com/en-us/company/partners/)
- [ Contact](https://www.minitab.com/en-us/company/contact-us/)
- [ Talk to Minitab](https://www.minitab.com/en-us/talk-to-minitab/)
- [ My Account](https://licensing.minitab.com/account/manage)
[](https://www.minitab.com/en-us/)
- Products
Back
[Products](https://www.minitab.com/en-us/products/)
[All Products](https://www.minitab.com/en-us/products/)
- [Minitab Solution Center](https://www.minitab.com/en-us/products/minitab-solution-center/)
- [Minitab Statistical Software](https://www.minitab.com/en-us/products/minitab/)
- [Minitab Connect](https://www.minitab.com/en-us/products/connect/)
- [Minitab Model Ops](https://www.minitab.com/en-us/products/model-ops/)
- [Minitab Education Hub](https://www.minitab.com/en-us/products/education-hub/)
- [Minitab Engage](https://www.minitab.com/en-us/products/engage/)
- [Minitab Workspace](https://www.minitab.com/en-us/products/workspace/)
- [Real-Time SPC](https://www.minitab.com/en-us/products/real-time-spc/)
- [Prolink Data Collection & SPC](https://www.minitab.com/en-us/products/prolink)
- [Simul8 Discrete Event Simulation](https://info.minitab.com/en/new-to-simul8?hsLang=en)
- [SPM](https://www.minitab.com/en-us/products/spm/)
- Solutions
Back
[Solutions](https://www.minitab.com/en-us/solutions/)
[All Solutions](https://www.minitab.com/en-us/solutions/)
- [Analytics](https://www.minitab.com/en-us/solutions/analytics/)
- [Statistics & Predictive Analytics](https://www.minitab.com/en-us/solutions/analytics/statistical-analysis-predictive-analytics/)
- [Data Science & Machine Learning](https://www.minitab.com/en-us/solutions/analytics/data-science-machine-learning/)
- [Business Analytics & Intelligence](https://www.minitab.com/en-us/solutions/analytics/business-analytics-intelligence/)
- [Statistical Process Control](https://www.minitab.com/en-us/solutions/analytics/statistical-process-control/)
- [Quality Analytics](https://www.minitab.com/en-us/solutions/analytics/quality-analytics/)
- [Live Analytics](https://www.minitab.com/en-us/solutions/analytics/live-analytics/)
- [Reliability & Life Data Analysis](https://www.minitab.com/en-us/solutions/analytics/reliability/)
- [Discrete Event Simulation](https://info.minitab.com/en/new-to-simul8?hsLang=en)
- [Process Mining](https://info.minitab.com/en/new-to-simul8?hsLang=en)
- [Key Capabilities](https://www.minitab.com/en-us/solutions/key-capabilities/)
- [Continuous Improvement](https://www.minitab.com/en-us/solutions/key-capabilities/continuous-improvement/)
- [Data Integration & Data Prep](https://www.minitab.com/en-us/solutions/key-capabilities/data-integration-data-prep/)
- [Diagramming & Mind Mapping](https://www.minitab.com/en-us/solutions/key-capabilities/diagramming-mind-mapping/)
- [Digital Twins](https://info.minitab.com/en/new-to-simul8?hsLang=en)
- [Model Deployment & ML Ops](https://www.minitab.com/en-us/solutions/key-capabilities/model-deployment-ml-ops/)
- [Innovation & Project Management](https://www.minitab.com/en-us/solutions/key-capabilities/innovation-project-management/)
- [Process Excellence: Detect, Correct & Prevent](https://www.minitab.com/en-us/solutions/key-capabilities/process-excellence/)
- [Featured Industries](https://www.minitab.com/en-us/solutions/industry/)
- [Academic](https://www.minitab.com/en-us/solutions/industry/academic/)
- [Energy & Natural Resources](https://www.minitab.com/en-us/solutions/industry/energy-resources/)
- [Government & Public Sector](https://www.minitab.com/en-us/solutions/industry/government/)
- [Healthcare](https://www.minitab.com/en-us/solutions/industry/healthcare/)
- [Insurance](https://www.minitab.com/en-us/solutions/industry/insurance/)
- [Manufacturing & Industrial](https://www.minitab.com/en-us/solutions/industry/manufacturing-industrial/)
- [Services](https://www.minitab.com/en-us/solutions/industry/service-industries/)
- [Software & Technology](https://www.minitab.com/en-us/solutions/industry/software-technology/)
- [Construction](https://www.minitab.com/en-us/solutions/industry/construction/)
- [Featured Roles](https://www.minitab.com/en-us/solutions/role/)
- [Engineering](https://www.minitab.com/en-us/solutions/role/engineering/)
- [Business Analysis](https://www.minitab.com/en-us/solutions/role/business-analysts/)
- [Information Technology](https://www.minitab.com/en-us/solutions/role/information-technology/)
- [Supply Chain](https://www.minitab.com/en-us/solutions/role/supply-chain/)
- [Customer Service & Contact Center](https://www.minitab.com/en-us/solutions/role/customer-service-contact-center/)
- [Human Resources](https://www.minitab.com/en-us/solutions/role/human-resources/)
- [Marketing](https://www.minitab.com/en-us/solutions/role/marketing/)
- [Research and Development](https://www.minitab.com/en-us/solutions/role/research-and-development/)
- Resources & Services
Back
[Resources & Services](https://www.minitab.com/en-us/resources-services/)
[All Resources & Services](https://www.minitab.com/en-us/resources-services/)
- [Resources](https://www.minitab.com/en-us/resources-services/resources/)
- [Case Studies](https://www.minitab.com/en-us/resources-services/resources/case-studies/)
- [eBooks & White Papers](https://www.minitab.com/en-us/resources-services/resources/ebooks-and-white-papers/)
- [Blog](https://blog.minitab.com/blog/?hsLang=en)
- [Data Sets](https://www.minitab.com/en-us/resources-services/resources/data-set/)
- [Webinars & Events](https://www.minitab.com/en-us/resources-services/resources/events/)
- [Education Hub](https://www.minitab.com/en-us/resources-services/resources/education-hub/)
- [Services](https://www.minitab.com/en-us/resources-services/services/)
- [Training](https://www.minitab.com/en-us/resources-services/services/training/)
- [Deployment](https://www.minitab.com/en-us/resources-services/services/deployment/)
- [Consulting](https://www.minitab.com/en-us/resources-services/services/statistical-consulting/)
- [Self-Paced Learning](https://www.minitab.com/en-us/resources-services/services/self-paced-learning/)
- [Continuing Education](https://www.minitab.com/en-us/resources-services/services/continuing-education/)
- Support
Back
[Support](https://www.minitab.com/en-us/support/)
[Technical Support](https://www.minitab.com/en-us/support/)
- [Subscriptions & Activation](https://www.minitab.com/en-us/support/subscriptions-and-activation/)
- [Minitab Quick Start](https://www.minitab.com/en-us/support/quick-start/)
- [Training](https://www.minitab.com/en-us/resources-services/services/training/)
- [Installation Support](https://www.minitab.com/en-us/support/installation/)
- [Support Videos](https://www.minitab.com/en-us/support/videos/)
- [Support Documentation](https://www.minitab.com/en-us/support/documents/)
- [Software Updates](https://www.minitab.com/en-us/support/software-updates/)
- [Product Downloads](https://www.minitab.com/en-us/support/downloads/)
- [Support Policy](https://www.minitab.com/en-us/support/policy/)
- Company
Back
[Company](https://www.minitab.com/en-us/company/)
[Company](https://www.minitab.com/en-us/company/)
- [About Us](https://www.minitab.com/en-us/company/our-company/)
- [Leadership Team](https://www.minitab.com/en-us/company/leadership-team/)
- [Partners](https://www.minitab.com/en-us/company/partners/)
- [Careers](https://www.minitab.com/en-us/company/careers/)
- [Contact](https://www.minitab.com/en-us/company/contact-us/)
- [News](https://www.minitab.com/en-us/company/press-releases/)
[Try/Buy](https://www.minitab.com/en-us/try-buy/)
- [Statistics](https://blog.minitab.com/en/blog/tag/statistics)
- [Data Analysis](https://blog.minitab.com/en/blog/tag/data-analysis)
-
- [Quality Improvement](https://blog.minitab.com/en/blog/tag/quality-improvement)
- [Subscribe](https://info.minitab.com/blog/subscribe?hsLang=en)
## Notice
You are now leaving minitab.com.
Click Continue to proceed to:
Continue
Go Back
# A Closer Look at Probability and Survival Plots
Minitab Blog Editor | 6/8/2015
Topics: [Data Analysis](https://blog.minitab.com/en/blog/tag/data-analysis), [Quality Improvement](https://blog.minitab.com/en/blog/tag/quality-improvement), [Reliability Analysis](https://blog.minitab.com/en/blog/tag/reliability-analysis), [Six Sigma](https://blog.minitab.com/en/blog/tag/six-sigma)
- [Share](https://www.linkedin.com/shareArticle?mini=true&url=https://blog.minitab.com/en/blog/quality-data-analysis-and-statistics/a-closer-look-at-probability-and-survival-plots)
- [Share](https://www.facebook.com/sharer.php?u=https://blog.minitab.com/en/blog/quality-data-analysis-and-statistics/a-closer-look-at-probability-and-survival-plots)
I recently fielded an interesting question about the probability and survival plots in Minitab [Statistical Software](http://www.minitab.com/products/minitab)'s Reliability/Survival menus:
*Is there a one-to-one match between the confidence interval points on a probability plot and the confidence interval points on survival plot at a specific percentile?*
Now, this may seem like an easy question, given that the probabilities on a survival plot are simply 1 minus the failure probabilities on a probability plot at a specific time t or stressor (in the case of Probit Analysis, used for our example below).
This can be seen here, at the 10th percentile:
The probability plot is saying that at a voltage of 113.25, 10% of your items are failing. Conversely, the survival plot will show that 90% of your items will survive at that same voltage.
How do the graphs compare when adding confidence intervals to both graphs? Before we get our hands dirty with this, let’s first review some terms and methods to get us comfortable enough to proceed further.
## Reliability/Survival Analysis
This is the overarching classification of tools within Minitab that help with modeling life data. Distribution Analysis, Repairable Systems Analysis, and Probit Analysis fall within this category.
## Probit Analysis
This analysis will be used as our example today. Probit analysis is used when you want to estimate percentiles and survival probabilities of an item in the presence of a stress. The response is required to be binomial in nature (go/no go, pass/fail). One example of a probit analysis could be testing light bulb life at different voltages.
Since the response data is binomial, you’d have to specify what would be a considered an event for that light bulb at a certain voltage. Let’s say the event is a light bulb blowing out before 800 hours.
Excerpt of data set
| Blows(The Event) | Trials | Volts |
| --- | --- | --- |
| 2 | 50 | 108 |
| 6 | 50 | 114 |
| 11 | 50 | 120 |
| 45 | 50 | 132 |
## Probability Plot
This graph plots each value against the percentage of values in the sample that are less than or equal to it, along a fitted distribution line (middle line). In probit analysis, it helps determine, at certain voltages, what the percentage of bulbs fail before 800 hours.
## Survival Plot
This graph displays a plot of the survival probabilities versus time. Each plot point represents the proportion of units surviving at time t. In probit analysis, it helps determine, at a certain voltages, what the percentage of bulbs survive beyond 800 hours.
## Back to the original question…
Can we take a value along the CI of a probability plot and find its corresponding value on the CI of survival plot at a specific percentile? Here are the confidence interval values for the percentile at 113.246:
If we add the above confidence interval values for the 10th percentile to the survival plot, you'll see that they don’t quite equal what’s shown at 90%. They’re a *little* off:
## The Reason
In our probability plot, the confidence interval is calculated with the parameter of interest being the percentile. Let’s look at the 10th percentile again:
Our 95% CI (111.302 to 114.779) is around the value of 113.246 volts. In our survival plot, the confidence interval is calculated around the probability of survival. You can see this in the session window under the Table of Survival Probabilities. The 95% CI around the survival probability of 0.90 for a voltage of 113.246:
Here’s another look at our survival plot with our aforementioned survival probabilities added:
They all nicely fit on one straight vertical line at voltage = 113.246.
This all being said, you *can* convert the lower bound or upper bound of a percentile to a point on a survival plot. Let’s say we look at the lower bound for 113.246 (which is 111.302). We’d first have to find the survival probability for that value:
Now let’s look at that table of survival probabilities for 0.90 again:
Notice that the survival probability for the lower CI of 113.246 ends up being the upper bound of the survival probability of 0.90. Given that the survival probabilities are one minus the failure probabilities, it makes sense that you'd have to look at the upper bound of a survival plot when analyzing the lower bound of a probability plot.
I hope this post helps you develop a deeper understanding of the relationship between our probability and survival plots—and I hope it wasn't *too* technical!
Please check out these other posts on Reliability/Survival:
[Probit Analysis: Down Goes the Meathouse!](https://blog.minitab.com/blog/statistics-and-quality-data-analysis/probit-analysis-down-goes-the-meathouse?hsLang=en)
[The Care and Feeding of Capital Equipment( with Reliability Statistics)](https://blog.minitab.com/blog/the-statistics-of-science/reliability-statistics-and-the-care-and-feeding-of-capital-equipment?hsLang=en)
## You Might Also Like
[New Minitab Updates Unite Data Collection, Preparation, and Predictive Analytics](https://blog.minitab.com/en/blog/new-minitab-updates-unite-data-collection-preparation-and-predictive-analytics?hsLang=en)
[Data Preparation](https://blog.minitab.com/en/blog/tag/data-preparation) | 5 Minute Read
[Artemis II Heat Shield: How Do You Decide in Uncertain Conditions?](https://blog.minitab.com/en/blog/artemis-ii-heat-shield-how-do-you-decide-under-uncertainty?hsLang=en)
[Data Analysis](https://blog.minitab.com/en/blog/tag/data-analysis) | 4 Minute Read
[Do You Really Need That New Machine? How Minitab Can Help You Find Out](https://blog.minitab.com/en/blog/do-you-really-need-that-new-machine-how-minitab-can-help-you-find-out?hsLang=en)
[Quality Improvement](https://blog.minitab.com/en/blog/tag/quality-improvement) | 4 Minute Read
---
- [Careers](https://www.minitab.com/en-us/company/careers/)
- [Trust Center](https://www.minitab.com/en-us/trust-center/)
- [Suppliers](https://www.minitab.com/en-us/suppliers/)
- [Site Map](https://www.minitab.com/en-us/site-map/)
- [](https://www.linkedin.com/company/minitab/)
- [](https://www.facebook.com/Minitab/)
- [](https://www.youtube.com/user/MinitabInc)
- [](https://www.instagram.com/minitab/)
---
© 2025 Minitab, LLC. All Rights Reserved.
- [Terms of Use](https://www.minitab.com/en-us/legal/terms-of-use/)
- [Privacy Policy](https://www.minitab.com/en-us/legal/privacy-policy/)
- [Legal](https://www.minitab.com/en-us/legal/)
- Cookies Settings