can I change the data type for a Standard Folio in RGA 7?
Once you have created a Data Sheet
Standard Folio, you cannot change the data type. For several
data types, however, you can transfer the data set to a
new Data Sheet that has been configured for a different data type. Transferring
is available for the following data types:
- Times-to-Failure Data - Multiple Systems
- Concurrent Operating Times
- Multiple Systems with Dates
- Multiple Systems with Event Codes
- Fielded Systems Data
You can choose to transfer data from any of these data
types to any other of these data types. To do this, choose
Data > Transfer to New Data Type or click the
Transfer to New Data Type icon on the Main page of the
Standard Folio Control Panel.
The Transfer to New Data Type window will appear,
allowing you to select a data type into which you would
like to transfer the data from the current Data Sheet.
When you make your selection and click OK,
the new Data Sheet will be added to the current Folio.
can I evaluate the accelerated life test design recommended
by ALTA’s test planning utility?
The accelerated test plan utility
7 has options to help you evaluate the test design
based on the conclusions you want to obtain from analyzing
the test data. There are three factors you can manipulate
to determine whether the design will meet your needs: confidence
level, bounds ratio and sample size.
Bounds ratio is defined as the ratio between the upper
and lower confidence bounds. It helps you determine the
relative size of the variance of the B(X) life estimate
you may obtain if you implement the test design and analyze
the data that you record. The relationship between the bounds
ratio, confidence level and sample size is summarized as
- The higher the required confidence level, the wider
the confidence interval; therefore, a larger bounds
- The larger the sample size, the narrower the confidence
interval; therefore, a smaller bounds ratio.
Consider the sample test plan shown next. In the Control
Panel on the right side of the result Folio, you can see
that for a 90% confidence level and a sample size of 20,
the calculated bounds ratio is approximately 3.53.
If the bounds ratio is determined to be too wide, then
you have the option to either accept a lower confidence
level or increase the sample size. You can experiment with
different adjustments to find an acceptable solution. You
also have the option to return to the test plan setup window,
select a different test plan method and generate a new design
that may be more suitable.
ALTA 7 also provides a simulation tool called
SimuMatic® that you can use to visualize the confidence
bounds associated with the bounds ratio presented in the
test plans utility. The test plans utility uses an analytical
solution that is based on the assumption of large sample
size; the simulation tool does not make any assumptions
about the sample size and thus may be preferred in the case
of small sample sizes. For a comparison of the analytical
solution vs. simulation results, see