بنك الأسئلة
يقوم موقع بي سمارت بتقديم العديد من الخدمات لجميع طلاب الوطن العربي في مختلف المراحل الدراسية
What does attribute
charts used for? Mention different types of attribute control charts and
explain each type
Attribute Control Charts are a set of control charts specifically designed for tracking
defects (also called non-conformities). These types of defects are binary in
nature (yes/no), where a part has one or more defects, or it doesn’t. Examples
of defects are paint scratches, discolorations, breaks in the weave of a
textile, dents, cuts, etc. Think of the last car that you bought. The defects
in each sample group are counted and run through some statistical calculations.
Depending on the type of Attribute Control Chart, the number of
defective parts are tracked (p-chart and np-chart), or alternatively, the
number of defects are tracked (u-chart, c-chart).
P-Charts
The
p-Chart, also known as the Fraction Defective Parts Chart, is the most common
of the Attribute Control Charts. For a sample subgroup, the number of defective
parts is measured and plotted as a fraction of the total subgroup sample size. It
is used for variable and constant sample size
NP-Chart
The
np=Chart is also known as the Number Defective Parts, and Number Non-Conforming
Parts Chart For a sample subgroup, the number of defective parts is measured
and plotted as a simple count. It is used for constant sample size
U-Chart
The
u-Chart is also known as the Number of Defects per Unit or Number of
Nonconformities per Unit Chart. For a sample subgroup, the number of times a
defect occurs is measured and plotted as either a percentage of the total
subgroup sample size, or a fraction of the total subgroup sample size. It is
used for variable and constant sample size
C-Chart
The u-Chart is also known as the Number of Defects per
sample or Number of Nonconformities per sample Chart. For a sample subgroup,
the number of times a defect occurs is measured and plotted. It is used for
constant sample size
"Number
defects or nonconformities" control charts (c-charts) can only be used
with variable sample size
A. True
B. False
B. False
Number of nonconforming
control charts are called as np-chart.
A. True
B. False
A. True
The 3 – sigma upper limit for a control chart for average number of nonconformities per unit, is expressed by ___________
a) UCL=u ̅+3√(u ̅/n)
b) UCL=u ̅-3√(u ̅/n)
c) UCL=u ̅-2√(u ̅/n)
d) UCL=u ̅-3/2 √(u ̅/n)
a) UCL=u ̅+3√(u ̅/n)
The sample for the control chart for
nonconformities is assumed to have, a variable sample size, and the sample
conformities distributed according to Normal distribution.
a) True
b) False
b) False
If xi=total number of nonconformities in a sample of ni inspection units, and there are N samples of different sample size, and x varies according to a Poisson distribution, what will be the value of center line of the u-chart?
a) u ̅=(∑_(i=1)^N▒〖2x〗_i/n_i )/N
b) u ̅=(∑_(i=1)^N▒x/〖2n〗_i )/2N
c) u ̅=(∑_(i=1)^N▒x_i/n_i )/N
d u ̅=(∑_(i=1)^N▒x_i/n_i )/2N
c) u ̅=(∑_(i=1)^N▒x_i/n_i )/N