Minitab calculates the planning estimate for the parameter that you want to estimate based on what you provide for the planning values, failure time distribution, and relationship between failure times and stress.
Example output
Type I right-censored data (Single Censoring)
Arrhenius model
Estimated parameter: Reliability at time = 360
Calculated planning estimate = 0.666228
Design stress value = 45
Planning Values
Percentile values = 90, 90 for percents = 0.5, 70 at stresses = 50, 125
Selected test plans: “Optimum” allocations test plans
Interpretation
For the capacitor data:
- You plan to estimate the reliability at 360 days.
- For the 360-day reliability, the calculated planning
estimate is 0.666228 at the design stress value of
45. Minitab calculates this estimate from your
planning values for the slope and intercept. That
is, for a Weibull distribution with a shape of 3.5
and an Arrhenius model with an intercept of −2.30114
and a slope of 0.231511, the 360-day reliability is
0.666228.
- The target confidence level is 95%. Because the resulting sample size must be rounded to an integer value, you cannot achieve a confidence level of exactly 95%. Your actual confidence level is slightly higher than the target confidence level.
