Data Entry Worksheet Features
Random uncertainty in measurements made using
measuring (MTE) and/or subject (SU) parameters can be estimated by entering limits and confidence
levels into the error source table of Measurement
Process Uncertainty Worksheet. Alternatively, random uncertainty can also be calculated
statistically by entering measurement results into the built-in
Parameter Data Entry Worksheets, which are accessed by clicking the MTE Random and SU
Random buttons on the Measurement Process Uncertainty Worksheet.
The Parameter Data Entry Worksheets can also be accessed by selecting the Measurement
Sample option on the Enter Data menu on the Measurement
Process Uncertainty Worksheet Parameter Data Entry Worksheet functions and
features are described below.
entries and associated statistics are accepted and the closed by
selecting OK on the menu. Conversely, new entries or
changes are ignored and the screen closed by selecting Cancel on
the menu. Data entries can be cut, copied, pasted, or deleted via
the Edit menu. Rows in the measurement data table can also
be inserted or deleted via the Edit menu. Selecting Run on the
menu opens the Run External
Application Screen, which can be used to launch external Windows
applications from within AccuracyRatio.
Data Entry Options
Up to 200 values can be entered in the measurement data table.
Data can be entered either as measurement results in nominal units by
selecting the Measurements option, or as deviations from nominal in parameter tolerance
offset units by selecting the Deviations option. For example, suppose the length of a gage block
has a nominal or reported value of 5 cm.
Measurements taken on the gage block can be entered directly in terms of centimeters or as deviations from 5 cm in terms of mm.
If you already have samples of measurements stored on an external spreadsheet, you don't need to
retype the results into the Parameter Data Entry Worksheet. Data can be copied
from the external application file into the Windows clipboard and pasted
into measurement data table via the Run External Application Screen.
Computed statistics are displayed directly below the measurement data
table. If the Measurements option is selected, then the sample Mean
Value is displayed. If the Deviations option is selected, then
the Mean Deviation is displayed. The Sample Size and
Standard Deviation are displayed for both options. The Mode
or Nominal Value entered into the Parameter
Bias Uncertainty Worksheet is also displayed for reference.
When the uncertainty in the mean value of the sample of measurements is
of primary concern, then you want to set the random uncertainty equal to
the Std Deviation of the Mean by checking the Use Std Deviation
in the Mean box. Mathematically speaking, the standard deviation
of the mean is equal to the standard deviation divided by the square
root of the sample size.