Question 1

Which of the following control charts are based on sample sizes as small as one?
A) 
B)R
C)c
D)p

Accepted Answer

The answer of Which of the following control charts are...

Question 2

Which of the following control charts is used to monitor the number of defective items within a sample?
A) 
B)R
C)c
D)p

Accepted Answer

The answer of Which of the following control charts is...

Question 3

Which of the following control charts is used to control the variation between samples?
A) 
B)R
C)c
D)p

Accepted Answer

Control chart A, also known as the X-bar chart, is used to control the variation between samples in a process. It tracks the average value of a sample over time and compares it to upper and lower control limits to determine if the process is in control or not. Choice B (R chart) is used to control the variation within a sample, while choices C (c chart) and D (p chart) are used for monitoring the proportion of nonconforming items in a process.

Question 4

If a sample of 40 units of output found 500 defects,then the 3-sigma upper control limit for the  chart would be
A)12.5.
B)23.11.
C)37.5.
D)75.0.

Accepted Answer

The answer of If a sample of 40 units of...

Question 5

In general,a process is considered to be in control for all the following conditions except
A)no points are outside the control limits.
B)all points are above the centre line.
C)the points are randomly distributed following a normal population.
D)no pattern exists in the plotted points (no evidence of a run).

Accepted Answer

All points being above the center line would indicate that the process is consistently producing results higher than the expected value, which would not be considered in control. A process is considered to be in control if there are no points outside the control limits, the points are randomly distributed following a normal population, and no pattern exists in the plotted points (no evidence of a run).

Question 6

If the quality of a process's output is determined by the number of defects within a small sample,use a(n)___ control chart.
A) 
B)R
C)c
D)p

Accepted Answer

The answer of If the quality of a process's output...

Question 7

If the quality of a process's output is determined by the difference between the largest and smallest values in a sample,use a(n)___ control chart.
A) 
B)R
C)c
D)p

Accepted Answer

The range control chart (R chart) is used to monitor the variability of a process by plotting the range (difference between the largest and smallest values) of a sample over time. This is the appropriate chart to use when the quality of a process's output is determined by the range of values. The other control charts listed (A, C, D) are not specifically designed to monitor range and may not be the best choice for this situation.

Question 8

A process is generally considered to be in control when
A)there are no sample points outside the control limits.
B)most points are near the centre line,without many being close to the control limits.
C)sample points are randomly distributed equally above and below the centre line.
D)all of the above are true.

Accepted Answer

All three criteria must be met for a process to be considered in control. The absence of sample points outside the control limits (A) ensures that the process is not exhibiting any significant variation beyond the normal variation. However, a process can be in control with a few points close to the control limits, as long as most points are close to the centre line (B). The randomness and symmetry of sample points above and below the centre line (C) indicate that the process is stable and has no systematic or assignable causes of variation. Therefore, when all three criteria are met, the process is considered to be in control.

Question 9

Which of the following control charts are often based on sample sizes larger than one hundred?
A) 
B)R
C)c
D)p

Accepted Answer

The answer of Which of the following control charts are...

Question 10

If the quality of a process's output is determined by the average value of a sample,use a(n)___ control chart.
A) 
B)R
C)c
D)p

Accepted Answer

An average control chart (also called an X-bar control chart) is used to monitor the average value of a sample and determine if it is within acceptable limits. This type of control chart is best suited for processes where the output quality is determined by the average value of a sample.

Question 11

A company randomly selects 100 light bulbs every day for 40 days from its production process.If 600 defective light bulbs are found in the sampled bulbs then the 3-sigma lower control limit would be
A)0.0357.
B)0.0429.
C)0.15.
D)0.1857.

Accepted Answer

The proportion of defective bulbs can be estimated using the sample proportion:
p̂ = 600/(100*40) = 0.15

The standard error for the sample proportion can be calculated using the formula:
SE = sqrt(p̂(1-p̂)/n)
where n is the sample size, which is 100 for each day in this case. 
SE = sqrt(0.15(1-0.15)/100) = 0.0387

The 3-sigma lower control limit for a process control chart can be calculated as:
LCL = p̂ - 3*SE
LCL = 0.15 - 3*0.0387 = 0.0342

Therefore, the closest choice is B, which is 0.0429.

Question 12

To monitor the number of blemishes on a polished surface,a company randomly selects 10 units of output from its process and counts the number of blemishes on each unit.The sample results are shown below:  Given the sample information above,the average number of defects per unit for this process would be
A)160.
B)80.
C)16.
D)10.

Accepted Answer

To find the average number of defects per unit, we need to calculate the mean of the given sample data:

Mean = (11 + 8 + 17 + 13 + 16 + 9 + 12 + 15 + 3 + 6) / 10 = 100 / 10 = 10

Therefore, the average number of defects per unit for this process is 10, which is option D in the given choices.

Question 13

Which of the following control charts is used to control the variation within samples?
A) 
B)R
C)c
D)p

Accepted Answer

The answer of Which of the following control charts is...

Question 14

If the quality of a process's output is determined by classifying the output as being defective or not defective,use a(n)___ control chart.
A) 
B)R
C)c
D)p

Accepted Answer

The answer of If the quality of a process's output...

Question 15

If a sample of 40 units of output found 500 defects,then the centre line for monitoring the average number of defects per unit of output would be
A)  = 40.
B)  = 0.08.
C)  = 12.5.
D)  = 20,000.

Accepted Answer

The answer of If a sample of 40 units of...

Question 16

A company randomly selects 100 light bulbs every day for 40 days from its production process.If 600 defective light bulbs are found in the sampled bulbs then the estimate for the process average defective would be
A)6.667.
B)0.167.
C)0.150.
D)0.250.

Accepted Answer

To estimate the process average defective, we need to use the sample proportion of defective bulbs found in the sampled bulbs.

Sample proportion of defective bulbs = (Total defective bulbs in the 40 days)/(Total bulbs sampled in the 40 days)
= 600/(100*40)
= 0.15

Therefore, the estimate for the process average defective is 0.15 or 15%.

The best choice is C, 0.150.

Question 17

To monitor the number of blemishes on a polished surface,a company randomly selects 10 units of output from its process and counts the number of blemishes on each unit.The sample results are shown below:  Given the sample information above,the standard deviation of the number of defects for this process would be
A)16.
B)10.
C)4.
D)0.

Accepted Answer

To find the standard deviation, we need to calculate the variance first. The formula for variance is:

s^2 = Σ(x-μ)^2/n

Where s^2 is the variance, Σ is the sum of, x is the number of blemishes on each unit, μ is the mean of the number of blemishes, and n is the sample size (10 in this case).

First, we need to find the mean (μ) of the number of blemishes:

μ = Σx/n = (2 + 6 + 0 + 1 + 4 + 3 + 5 + 0 + 7 + 2)/10 = 3

Next, we can plug in the values to calculate the variance:

s^2 = [(2-3)^2 + (6-3)^2 + (0-3)^2 + (1-3)^2 + (4-3)^2 + (3-3)^2 + (5-3)^2 + (0-3)^2 + (7-3)^2 + (2-3)^2]/10
s^2 = 56/10
s^2 = 5.6

Finally, we take the square root of the variance to get the standard deviation:

s = √5.6 ≈ 2.37

Therefore, the best choice is C, with a standard deviation of about 2.37.

Question 18

Which of the following charts are frequently used together to monitor and control quality?
A)p/ 
B)R/p
C)c/R
D)R/

Accepted Answer

The answer of Which of the following charts are frequently...

Question 19

A control chart that reflects the amount of dispersion,or spread,present within each sample is known as a(n)
A)p-chart
B)c-chart
C)R-chart
D)  -chart

Accepted Answer

The R-chart, or Range chart, measures the dispersion within each sample by plotting the range (highest value minus lowest value) of each sample. This chart is useful for detecting changes in variability over time. The p-chart and c-chart are used for monitoring the proportion of nonconforming items in a sample or process, while the 11eac5d1_2912_8e7a_888f_81e23c61830e_TB7749_11-chart (also known as the X-bar chart) is used to track changes in the average value of a sample or process.

Question 20

Which of the following control charts is based on the number of defects within a sample?
A) 
B)R
C)c
D)p

Accepted Answer

The answer of Which of the following control charts is...

Quiz 3: Statistical Process Control

Which of the following control charts are based on sample sizes as small as one?

Which of the following control charts is used to monitor the number of defective items within a sample?

Which of the following control charts is used to control the variation between samples?

If a sample of 40 units of output found 500 defects,then the 3-sigma upper control limit for the chart would be

In general,a process is considered to be in control for all the following conditions except

If the quality of a process's output is determined by the number of defects within a small sample,use a(n) ___ control chart.

If the quality of a process's output is determined by the difference between the largest and smallest values in a sample,use a(n) ___ control chart.

A process is generally considered to be in control when

Which of the following control charts are often based on sample sizes larger than one hundred?

If the quality of a process's output is determined by the average value of a sample,use a(n) ___ control chart.

A company randomly selects 100 light bulbs every day for 40 days from its production process.If 600 defective light bulbs are found in the sampled bulbs then the 3-sigma lower control limit would be

Which of the following control charts is used to control the variation within samples?

If the quality of a process's output is determined by classifying the output as being defective or not defective,use a(n) ___ control chart.

If a sample of 40 units of output found 500 defects,then the centre line for monitoring the average number of defects per unit of output would be

A company randomly selects 100 light bulbs every day for 40 days from its production process.If 600 defective light bulbs are found in the sampled bulbs then the estimate for the process average defective would be

Which of the following charts are frequently used together to monitor and control quality?

A control chart that reflects the amount of dispersion,or spread,present within each sample is known as a(n)

Which of the following control charts is based on the number of defects within a sample?