Question 1

A run chart is simply a control chart with two additional horizontal lines.

Accepted Answer

A run chart is a graphical tool used to track changes or trends in data over time, typically used for quality control purposes. It does not have any horizontal lines, unlike a control chart which has a centerline, upper control limit, and lower control limit.

Question 2

Statistical quality control is necessary because no two outputs from any production process are exactly alike.

Accepted Answer

This is true because there will always be variations in the output due to various factors such as machine settings, operator capabilities, raw material quality, etc. Statistical quality control helps to identify and control these variations to ensure that the output meets the desired quality requirements.

Question 3

The travel tube of Biker Smellum Good has a lower specification weight of 0.5 ounces and an upper specification limit of 0.52 ounces.The standard deviation is 0.01 ounces.What is the process capability index if the process appears to be in statistical control?
A)0.0003
B)0.3333
C)1.00
D)2.00

Accepted Answer

The answer of The travel tube of Biker Smellum Good...

Question 4

Control limits are chosen statistically so that there is a high probability that sample statistics will fall randomly between the lower control limit and the upper control limit if the process is in control.

Accepted Answer

Control limits are specifically designed to indicate the range within which a process variable is expected to fluctuate in a state of statistical control, which means that variations in the process are due to common causes of variation only. Therefore, it is expected that sample statistics will fall randomly between the lower and upper control limits if the process is in control.

Question 5

For Super Soil,the lower specification fill weight is 35.0 pounds and the upper specification fill weight is 35.5 pounds.The filling process has a standard deviation of 0.4 pounds and the process is in control.Find the process capability index.
A)0.208
B)1.25
C)88.75
D)0.1

Accepted Answer

The process capability index (Cpk) is calculated as the minimum of the upper and lower process capability indices (Cpu and Cpl). In this case, the lower specification limit (LSL) is 35.0 pounds and the upper specification limit (USL) is 35.5 pounds. The process mean is not given, but we can assume that it is centered between the LSL and USL, or 35.25 pounds. The process standard deviation is 0.4 pounds.The upper process capability index (Cpu) is calculated as:Cpu = (USL - process mean) / (3 * process standard deviation)Cpu = (35.5 - 35.25) / (3 * 0.4)Cpu = 0.167The lower process capability index (Cpl) is calculated as:Cpl = (process mean - LSL) / (3 * process standard deviation)Cpl = (35.25 - 35.0) / (3 * 0.4)Cpl = 0.208The process capability index (Cpk) is the minimum of Cpu and Cpl, which in this case is 0.167. Therefore, the correct answer is A.

Question 6

Find the control limits for a p-chart with  = 0.022 obtained from fifty samples each of size 150.
A)LCL = -0.01 and UCL = 0.06
B)LCL = 0.19 and UCL = 0.25
C)LCL = -0.07 and UCL = 0.37
D)LCL = 0 and UCL = 0.06

Accepted Answer

The answer of Find the control limits for a p-chart...

Question 7

Process capability analysis should be used only after ________.
A)control charts indicate that all special causes have been eliminated
B)control charts show that the process is out of control
C)common and special causes are known
D)a plan for getting the process under statistical control has been agreed upon

Accepted Answer

Process capability analysis should only be performed after all special causes of variation have been eliminated, and the process is under statistical control. This ensures that the data used for the analysis are representative of the process's natural variation. The other options are not correct because process capability analysis cannot be performed when a process is out of control, and it is not necessary to have a plan to get the process under control to perform the analysis. Common and special causes are known is not necessarily a requirement for process capability analysis, but it does help in understanding the sources of variability in the process.

Question 8

All of the following are possible process capability situations except ________.
A)the natural variation in the output is smaller than the design tolerance
B)the natural variation and the design specifications are about the same size
C)the natural variation,the unnatural variation,and the design specifications are nearly the same
D)the range of process variation is larger than the design specifications

Accepted Answer

In all of the other options, the process is not capable of meeting the design specifications. In option C, the natural and unnatural variations are nearly the same as the design specifications, which indicates a capable process.

Question 9

Process capability analysis involves ________.
A)comparing the distribution of process output to specifications when only common and special causes are known to determine the variation
B)comparing the distribution of process output to specifications when only special causes determine the variation
C)comparing the distribution of process output to specifications when only common causes determine the variation
D)collecting data to prove a process is under statistical control

Accepted Answer

Process capability analysis involves comparing the distribution of process output to specifications when only common causes determine the variation, indicating the process is stable and predictable.

Question 10

The process capability index is calculated by ________.
A) 
B) 
C) 
D)

Accepted Answer

The answer of The process capability index is calculated by...

Question 11

The relationship between the process capability and the design specifications is measured by the ________.
A)process control index
B)process control monitor
C)process capability chart
D)process capability index

Accepted Answer

The process capability index (PCI) measures the ability of a process to consistently produce parts that meet design specifications. It takes into account both the process variability and the distance between the process mean and the specification limits. A value of 1 means the process is performing perfectly, while values less than 1 indicate that the process is producing parts outside of the design specifications. As such, the PCI is the best measure of the relationship between process capability and design specifications.

Question 12

Find the control limits for a p-chart with  = 0.36 found from ten samples of size 126,forty-two samples of size 124,and thirteen samples of size 135.
A)LCL = 0.232 and UCL = 0.488
B)LCL = 0.091 and UCL = 0.093
C)LCL = 0.390 and UCL = 0.494
D)LCL = 0 and UCL = 0.488

Accepted Answer

Firstly, we need to calculate the overall proportion defective (p) using the given data:
n1 = 126, n2 = 124, n3 =135
x1 = 11eabc4c_bb14_7d83_8797_87fe7a383fba_TB2972_11 = 0.36
x2 = unknown
x3 = unknown

The total number of units sampled is:
N = n1 + n2 + n3 = 126 + 124 + 135 = 385

The total number of defectives is:
x = n1x1 + n2x2 + n3x3 = 126(0.36) + 124x2 + 135x3

Since we don't know the values of x2 and x3, we assume that the proportion defective is the same over all samples. Therefore, we can use the overall proportion defective formula:

p = x/N = (126(0.36) + 124x2 + 135x3)/385

To find the control limits, we need to first calculate the centerline (p-bar) and the standard deviation of the proportion defective (σp).

p-bar = (n1p1 + n2p2 + n3p3)/N = (126(0.36) + 124p2 + 135p3)/385

σp = sqrt{∑[(ni/N)(pi-p-bar)^2]}

where i = 1,2,3 and pi = xi/ni.

Plugging in the values, we get:

σp = sqrt[(126/385)(0.36-p-bar)^2 + (124/385)(p2-p-bar)^2 + (135/385)(p3-p-bar)^2]

Next, we can calculate the control limits using the formulas:

LCL = p-bar - 3σp
UCL = p-bar + 3σp

Since we don't have values for p2 and p3, we use the worst-case scenario where they are both 0 (meaning no defectives in the remaining samples).

p-bar = (126(0.36) + 124(0) + 135(0))/385 = 0.126

σp = sqrt[(126/385)(0.36-0.126)^2 + (124/385)(0-0.126)^2 + (135/385)(0-0.126)^2] = 0.059

LCL = 0.126 - 3(0.059) = 0.232
UCL = 0.126 + 3(0.059) = 0.488

Therefore, the best answer is A (LCL = 0.232 and UCL = 0.488).

Question 13

The lower specification for ChocoChips candy kiddie bag is 12 candies while the upper specification limit is 15 candies.The standard deviation is 2 candies.If the process is in control,what is the process capability index?
A)1.47
B)8.82
C)0.25
D)1.5

Accepted Answer

The answer of The lower specification for ChocoChips candy kiddie...

Question 14

For Typhoon Shampoo,the lower specification fill weight is 15.0 ounces and the upper specification fill weight is 15.2 ounces.The filling process has a standard deviation of 0.04 ounces and the process appears to be in control.Find the process capability index.
A)1.6667
B)0.8333
C)0.0013
D)5.00

Accepted Answer

The process capability index can be calculated using the formula: 
Cp = (upper specification limit - lower specification limit) / (6 * standard deviation)
Substituting the given values, we get:

Cp = (15.2 - 15.0) / (6 * 0.04)
Cp = 0.2 / 0.24
Cp = 0.8333

Therefore, the process capability index is 0.8333, which is closest to option B.

Question 15

In manufacturing,the tolerance is the target value while the nominal specification is the permissible range around the tolerance.

Accepted Answer

In manufacturing, the nominal specification is the target value while the tolerance is the permissible range around the nominal specification.

Question 16

The distinction between quality control attributes and variables is not an important one because the same statistical process control tools are used for both.

Accepted Answer

The distinction between quality control attributes and variables is important as different statistical process control tools are used for each. Attributes refer to characteristics that can be counted or classified (e.g. number of defects), while variables refer to characteristics that can be measured on a continuous scale (e.g. temperature). Different tools are necessary for analyzing and improving each type of quality control.

Question 17

The canister of No Way Bug Spray has a lower specification weight of 3.5 fluid ounces and an upper specification limit of 3.6 fluid ounces.The process filling standard deviation is 0.1 fluid ounces.The process is found to be in control using the control charts.What is the process capability index?
A)0.50
B)1.00
C)2.00
D)0.167

Accepted Answer

The answer of The canister of No Way Bug Spray...

Question 18

All of the following are important elements of process capability except ________.
A)the design specifications
B)the centering of the process
C)the range of variation
D)the control limits

Accepted Answer

Control limits are related to the control of the process rather than its capability, which is about the process's ability to meet design specifications within its range of variation and centering.

Question 19

Find the control limits for a p-chart using the below information: 
A)LCL = 0.019 and UCL = 0.069
B)LCL = 0 and UCL = 0.016
C)LCL = 0.004 and UCL = 0.20
D)LCL = 0 and UCL = 0.069

Accepted Answer

The answer of Find the control limits for a p-chart...

Question 20

The sample statistics will fall randomly within the lower and the upper control limits when the process is in statistical control.

Accepted Answer

This is true. When the process is in statistical control, the sample statistics are expected to fall within the control limits, and any variations are due to random variation inherent in the process. If the sample statistics fall outside the control limits, it is an indication that the process is out of control and some corrective action may be necessary.

Quiz 8: Introduction to Statistical Quality Control

A run chart is simply a control chart with two additional horizontal lines.

Statistical quality control is necessary because no two outputs from any production process are exactly alike.

The travel tube of Biker Smellum Good has a lower specification weight of 0.5 ounces and an upper specification limit of 0.52 ounces.The standard deviation is 0.01 ounces.What is the process capability index if the process appears to be in statistical control?

Control limits are chosen statistically so that there is a high probability that sample statistics will fall randomly between the lower control limit and the upper control limit if the process is in control.

For Super Soil,the lower specification fill weight is 35.0 pounds and the upper specification fill weight is 35.5 pounds.The filling process has a standard deviation of 0.4 pounds and the process is in control.Find the process capability index.

Find the control limits for a p-chart with = 0.022 obtained from fifty samples each of size 150.

Process capability analysis should be used only after ________.

All of the following are possible process capability situations except ________.

Process capability analysis involves ________.

The process capability index is calculated by ________.

The relationship between the process capability and the design specifications is measured by the ________.

Find the control limits for a p-chart with = 0.36 found from ten samples of size 126,forty-two samples of size 124,and thirteen samples of size 135.

The lower specification for ChocoChips candy kiddie bag is 12 candies while the upper specification limit is 15 candies.The standard deviation is 2 candies.If the process is in control,what is the process capability index?

For Typhoon Shampoo,the lower specification fill weight is 15.0 ounces and the upper specification fill weight is 15.2 ounces.The filling process has a standard deviation of 0.04 ounces and the process appears to be in control.Find the process capability index.

In manufacturing,the tolerance is the target value while the nominal specification is the permissible range around the tolerance.

The distinction between quality control attributes and variables is not an important one because the same statistical process control tools are used for both.

The canister of No Way Bug Spray has a lower specification weight of 3.5 fluid ounces and an upper specification limit of 3.6 fluid ounces.The process filling standard deviation is 0.1 fluid ounces.The process is found to be in control using the control charts.What is the process capability index?

All of the following are important elements of process capability except ________.

Find the control limits for a p-chart using the below information:

The sample statistics will fall randomly within the lower and the upper control limits when the process is in statistical control.