Documentation

General information

In presence of several replicates per batch (scenario 4), the analysis is performed on the replicates average.

Descriptive statistics

Some descriptive statistics are displayed to summarize data.

Note: The unit of Out Of Specifications (OOS) results is defined in the user Preferences OSS Units.

Process stability

The process stability is a pre-requisite to perform a capability analysis. It is evaluated with the stability test which may detect drift and trend on data.

Note: Conclusion on Stability test is performed with an alpha risk of 1%.

Note: Stability test is performed only for scenarios 2, 3 and 4 (several batches).

Note: The test is not displayed if the number of batches <10. A warning message on the test relevance is displayed if the number of batches is >=10 and <20.

Tip: Cross validate stability test results with the Individual Control Chart to evaluate stability.

Normality test

Capability indices are based on the normality assumption. If the normality is not fulfilled, interpretation of capability results is not meaningful. These indices are replaced by capability indices based on the smooth curve.

Note: Conclusion on Normality Test is performed using the normality alpha level defined in the user settings if the number of observations is <1000. If n>=1000, the Normality Test is replaced by a conclusion based on the Skewness and Kurtosis.

Note: In presence of several batches (scenario 3), the Normality Test is performed on residuals from anova model with batch as a factor.

Note: If Force normality is set to YES in the user Preferences, all results which depend on Normality Test conclusion are performed assuming a normal distribution.

Capability results

Process capability is a measure of the ability of the process to meet specifications.

Capability indices such as Cp/Cpk are provided if data follow a normal distribution. These indices are replaced by Cnp/Cnpk if data do not follow a normal distribution.

Capability indices are calculated systematically with the long-term standard deviation. When calculated with several batches, they can be considered as a process performance index (Pp, Ppk, Pnp, Pnpk).

Note: Cnp/Cnpk are calculated from percentiles (X_0.135% and X_99.865%) of the smooth curve or data according the user Preference Cnpk formula.

Note: Conclusion is performed on Cpk/Cnpk using the threshold limit defined in the user Preference Capability thresholds.

Note: For minimal capability analysis, the formal capability analysis cannot be performed. The conclusion is performed on the minimum and/or maximum values compared with specifications.

Note: In presence of several responses per batch (scenario 3), capability analyses are also performed per batch if the number of observations per batch >=6

Expected Out Of Specifications (OOS) results

The expected Out Of Specifications (OOS) results inform on the future process performance.

Note: If data follow a normal distribution, expected OOS are estimated from the normal curve otherwise they are estimated from the smooth curve.

Note: The unit of expected OOS results is defined in the user Preference OOS unit.

Note: In presence of several responses per batch (scenario 3), expected OOS results are also performed per batch if the number of observations per batch >=6.

You do not have the same results with the same dataset

Check that the User preferences are the same for both studies.