If you have uncensored or right censored data and no distribution fits your data, the Nonparametric Distribution Analysis can be used to estimate cumulative failure probabilities, hazard rates and draw survival, cumulative failure and hazard plots.
At the Excel Menu (For Excel 2007, go to Add-ins first)
Choose ProcessMA > Reliability and Survival > Distribution Analysis (Right Censoring) > Nonparametric Distribution Analysis
In Variable, select the column containing the data (Numeric)
In Frequency, select the column containing frequency counts (Optional, Positive integer)
Under Censor Tab, in Censor, select the column containing censoring indicator (Optional, Exactly 2 distinct values - censored and uncensored)
Under Censor Tab, in Censor Value, choose the indicator you use to indicate censoring
Under Estimate Tab, in Confidence Level, enter the desired confidence level (Numeric, >0 & <1)
Under Graph Tab, check Survival Plot, if you want to display survival plot
Under Graph Tab, check Cumulative Failure Plot, if you want to display cumulative failure plot
Under Graph Tab, check Hazard Plot, if you want to display hazard plot
Under Graph Tab, check Show Confidence Interval, if you want to display confidence interval in the above plots
Click OK
You work in a manufacturing plant making widgets and you want to find out the time at which 5% of widgets will fail. You have collected failure times for 50 widgets but some widgets dropped out of the test. The failure times marked ‘F’ indicates actual failure times and ‘c’ indicates censored units. You want to find out the time at which half the widgets fail.
Open data worksheet by choosing ProcessMA > Tools > Data
Choose ProcessMA > Reliability and Survival > Distribution Analysis (Right Censoring) > Nonparametric Distribution Analysis
In Variable, select CD - Failure Times
Under Censor Tab, in Censor, select CE - Censor
Under Censor Tab, in Censor Value, choose C
Click OK
The estimated median failure time is 157 months.
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