Hioki RM3542, Инструкция по эксплуатации, Страница: 80 / 218

6.3 Performing Statistical Calculations on Measured Values
74
Statistical calculations can be performed on up to 30,000 measured values, with results displayed.
Printing is also available (p. 82).
Calculation types: average, maximum and minimum values, population standard deviation, sample
standard deviation, process compatibility indices
Deleting Statistical Calculation Results
Stored data is automatically erased at the following times:
6.3 Performing Statistical Calculations on
Measured Values
Maximum value Xmax = MAX (x
1
, ....., x
n
)
In these formulas, n represents the number of valid
data samples.
Hi and Lo are the upper and lower thresholds of the
comparator.
*. The process capability indices represent the quality
achievement capability created by a process, which
is the breadth of the dispersion and bias of the pro-
cess' quality. Generally, depending on the values of
Cp and CpK, process capability is evaluated as fol-
lows:
Cp, CpK>1.33 ......... Process capability is ideal
1.33

Cp, CpK>1.00 Process capability is adequate
1.00

Cp, CpK ......... Process capability is inade-
quate
Minimum value Xmin = MIN (x
1
, ....., x
n
)
Average
Population standard
deviation
Standard deviation
of sample
Process capability
index (dispersion) *
Process capability
index (bias)*
n
x
x



n
x
2
nx
2
–

n
----------------------------- =

n 1 –
x
2
nx
2
–

n 1 –
----------------------------- =
1
6



n
Lo Hi
Cp

1
6
2

   

n
x Lo Hi Lo Hi
CpK

• When only one valid data sample exists, standard deviation of sample and process capability indices are
not displayed.
• When

n-1
= 0, Cp and CpK are 99.99.
• The upper limit of Cp and CpK is 99.99. If Cp or CpK exceeds 99.99, the value 99.99 is displayed
• Negative values of CpK are handled as CpK = 0.
• If statistical calculation is turned off and then back on without first clearing calculation results, calculation
resumes from the point when it was turned off.
• Measurement speed is restricted when statistical calculation is enabled.
• When Auto-Memory is enabled (ON), statistical calculation is enabled (ON) by force.
• When statistical calculation is disabled (OFF), Auto-Memory is disabled (OFF) by force.
•
when the memory function setting (including data-mem-
ory) is changed (p. 142)
•
when the range is changed (p. 31)
•
when changing comparator settings (p. 34)
•
when printing the statistical calculations (p. 82)
•
when the DUT is changed (p. 28)
•
upon system reset (p. 67)
•
upon setting the auto-memory number of values to store
(p. 73)