Sqc – Statistical Quality Control

Statistical quality control (SQC) The application of statistical techniques to measure and evaluate the quality of a product, service, or process. Two basic categories: I. Statistical process control (SPC): – the application of statistical techniques to determine whether a process is functioning as desired II. Acceptance Sampling: – the application of statistical techniques to determine whether a population of items should be accepted or rejected based on inspection of a sample of those items. Quality Measurement: Attributes vs Variables Attributes:Characteristics that are measured as either â€Å"acceptable† or â€Å"not acceptable†, thus have only discrete, binary, or integer values. Variables: Characteristics that are measured on a continuous scale. Statistical Process Control (SPC) Methods Statistical process control (SPC) monitors specified quality characteristics of a product or service so as: To detect whether the process has changed in a way that w ill affect product quality and To measure the current quality of products or services. Control is maintained through the use of control charts. The charts have upper and lower ontrol limits and the process is in control if sample measurements are between the limits. Control Charts for Attributes P Charts – measures proportion defective. C Charts – measures the number of defects/unit. Control Charts for Variables X bar and R charts are used together – control a process by ensuring that the sample average and range remain within limits for both. Basic Procedure 1. An upper control limit (UCL) and a lower control limit (LCL) are set for the process. 2. A random sample of the product or service is taken, and the specified quality characteristic is measured. . If the average of the sample of the quality characteristic is higher than the upper control limit or lower than the lower control limit, the process is considered to be â€Å"out of control†. CONTROL CHA RTS FOR ATTRIBUTES p-Charts for Proportion Defective p-chart: a statistical control chart that plots movement in the sample proportion defective (p) over time Procedure: 1. take a random sample and inspect each item 2. determine the sample proportion defective by dividing the number of defective items by the sample size 3. lot the sample proportion defective on the control chart and compare with UCL and LCL to determine if process is out of control The underlying statistical sampling distribution is the binomial distribution, but can be approximated by the normal distribution with: mean = u = np (Note – add the bars above the means used in all the equations in this section) standard deviation of p: sigmap = square root of (p(1 -p ) / n) where p = historical population proportion defective and n = sample size Control Limits: UCL = u + z sigmap LCL = u – z sigma p is the number of standard deviations from the mean. It is set based how certain you wish to be that when a l imit is exceeded it is due to a change in the process proportion defective rather than due to sample variability. For example: If z = 1 if p has not changed you will still exceed the limits in 32% of the samples (68% confident that mean has changed if the limits are exceeded. z = 2 – limits will be exceeded in 4. 5 (95. 5 % confidence that mean has changed) z = 3 – limits will be exceeded in . 03 (99. % confidence) c-Charts for Number of Defects Per Unit c-chart: a statistical control chart that plots movement in the number of defects per unit. Procedure: 1. randomly select one item and count the number of defects in that item 2. plot the number of defects on a control chart 3. compare with UCL and LCL to determine if process is out of control The underlying sampling distribution is the Poisson distribution, but can be approximated by the normal distribution with: mean = c standard deviation = square root of c here c is the historical average number of defects/unit Con trol Limits: UCL = c + z c LCL = c – z c Control Charts for Variables Two charts are used together: R-chart (â€Å"range chart†) and X barchart (â€Å"average chart†) Both the process variability (measured by the R-chart) and the process average (measured by the X bar chart) must be in control before the process can be said to be in control. Process variability must be in control before the X bar chart can be developed because a measure of process variability is required to determine the -chart control limits.R-Chart for Process Variability: UCLR = D4(R) LCLR = D3(R) where is the average of past R values, and D3 and D4 are constants based on the sample size -Chart for Process Average: UCLR = X bar + A2(R) LCL = X bar – A2(R) where X bar is the average of several past values, and A2 is a constant based on the sample size Other Types of Attribute-Sampling Plans Double-Sampling Plan: Specifies two sample sizes (n1 and n2) and two acceptance levels (c1 and c2 ) 1. f the first sample passes (actual defects c1), the lot is accepted 2. if the first sample fails and actual defects > c2, the lot is rejected 3. if first sample fails but c1 < actual defects c2, the second sample is taken and judged on the combined number of defectives found. Sequential-Sampling Plan: Each time an item is inspected, a decision is made whether to accept the lot, reject it, or continue sampling. Acceptance Sampling Goal: To accept or reject a batch of items.Frequently used to test incoming materials from suppliers or other parts of the organization prior to entry into the production process. Used to determine whether to accept or reject a batch of products. Measures number of defects in a sample. Based on the number of defects in the sample the batch is either accepted or rejected. An acceptance level c is specified. If the number of defects in the sample is c the atch is accepted, otherwise it is rejected and subjected to 100% inspection. Sqc – Statistical Quality Control Statistical quality control (SQC) The application of statistical techniques to measure and evaluate the quality of a product, service, or process. Two basic categories: I. Statistical process control (SPC): – the application of statistical techniques to determine whether a process is functioning as desired II. Acceptance Sampling: – the application of statistical techniques to determine whether a population of items should be accepted or rejected based on inspection of a sample of those items. Quality Measurement: Attributes vs Variables Attributes:Characteristics that are measured as either â€Å"acceptable† or â€Å"not acceptable†, thus have only discrete, binary, or integer values. Variables: Characteristics that are measured on a continuous scale. Statistical Process Control (SPC) Methods Statistical process control (SPC) monitors specified quality characteristics of a product or service so as: To detect whether the process has changed in a way that w ill affect product quality and To measure the current quality of products or services. Control is maintained through the use of control charts. The charts have upper and lower ontrol limits and the process is in control if sample measurements are between the limits. Control Charts for Attributes P Charts – measures proportion defective. C Charts – measures the number of defects/unit. Control Charts for Variables X bar and R charts are used together – control a process by ensuring that the sample average and range remain within limits for both. Basic Procedure 1. An upper control limit (UCL) and a lower control limit (LCL) are set for the process. 2. A random sample of the product or service is taken, and the specified quality characteristic is measured. . If the average of the sample of the quality characteristic is higher than the upper control limit or lower than the lower control limit, the process is considered to be â€Å"out of control†. CONTROL CHA RTS FOR ATTRIBUTES p-Charts for Proportion Defective p-chart: a statistical control chart that plots movement in the sample proportion defective (p) over time Procedure: 1. take a random sample and inspect each item 2. determine the sample proportion defective by dividing the number of defective items by the sample size 3. lot the sample proportion defective on the control chart and compare with UCL and LCL to determine if process is out of control The underlying statistical sampling distribution is the binomial distribution, but can be approximated by the normal distribution with: mean = u = np (Note – add the bars above the means used in all the equations in this section) standard deviation of p: sigmap = square root of (p(1 -p ) / n) where p = historical population proportion defective and n = sample size Control Limits: UCL = u + z sigmap LCL = u – z sigma p is the number of standard deviations from the mean. It is set based how certain you wish to be that when a l imit is exceeded it is due to a change in the process proportion defective rather than due to sample variability. For example: If z = 1 if p has not changed you will still exceed the limits in 32% of the samples (68% confident that mean has changed if the limits are exceeded. z = 2 – limits will be exceeded in 4. 5 (95. 5 % confidence that mean has changed) z = 3 – limits will be exceeded in . 03 (99. % confidence) c-Charts for Number of Defects Per Unit c-chart: a statistical control chart that plots movement in the number of defects per unit. Procedure: 1. randomly select one item and count the number of defects in that item 2. plot the number of defects on a control chart 3. compare with UCL and LCL to determine if process is out of control The underlying sampling distribution is the Poisson distribution, but can be approximated by the normal distribution with: mean = c standard deviation = square root of c here c is the historical average number of defects/unit Con trol Limits: UCL = c + z c LCL = c – z c Control Charts for Variables Two charts are used together: R-chart (â€Å"range chart†) and X barchart (â€Å"average chart†) Both the process variability (measured by the R-chart) and the process average (measured by the X bar chart) must be in control before the process can be said to be in control. Process variability must be in control before the X bar chart can be developed because a measure of process variability is required to determine the -chart control limits.R-Chart for Process Variability: UCLR = D4(R) LCLR = D3(R) where is the average of past R values, and D3 and D4 are constants based on the sample size -Chart for Process Average: UCLR = X bar + A2(R) LCL = X bar – A2(R) where X bar is the average of several past values, and A2 is a constant based on the sample size Other Types of Attribute-Sampling Plans Double-Sampling Plan: Specifies two sample sizes (n1 and n2) and two acceptance levels (c1 and c2 ) 1. f the first sample passes (actual defects c1), the lot is accepted 2. if the first sample fails and actual defects > c2, the lot is rejected 3. if first sample fails but c1 < actual defects c2, the second sample is taken and judged on the combined number of defectives found. Sequential-Sampling Plan: Each time an item is inspected, a decision is made whether to accept the lot, reject it, or continue sampling. Acceptance Sampling Goal: To accept or reject a batch of items.Frequently used to test incoming materials from suppliers or other parts of the organization prior to entry into the production process. Used to determine whether to accept or reject a batch of products. Measures number of defects in a sample. Based on the number of defects in the sample the batch is either accepted or rejected. An acceptance level c is specified. If the number of defects in the sample is c the atch is accepted, otherwise it is rejected and subjected to 100% inspection.

Before and After the Cellphone Essay

Cellphones have gradually become an imperative part of peoples lives today. 70% of the world’s population have cellphones. These days, people and their mobile phones seem to be inseparable. Texting or calling someone when we wake up has become a usual habit just like brushing our teeth in the morning. For many of us, it’s hard to imagine a time before cellphones. Having a cellphone has changed our manners, the way we communicate, and our safety. Before cellphones there seemed to be more peace and quite. People seemed to have manners. Today people don’t always remember their manners when using their cellphones. People constantly carrying on personal conversations in a public place can be very annoying. Some people talk really loud and don’t care that everyone around them can hear every word they are saying. It can be extremely disturbing to someone when they are walking in a mall or down a street and someone starts speaking right beside or behind them. They turn to respond, only to find out he or she beside them has an earbud active. Before we had cellphones people would actually write letters. During my elementary school days it was â€Å"cool† to pass notes. We actually used complete sentences and words that were in the dictionary. Also before cellphones if someone was to leave the house, they didn’t make a phone call unless they popped 10 cents into a pay phone. People never received any calls away from home. People actually had to be out of touch with friends and family when they weren’t at home. Now that we have cell phones letters are rarely sent. Today note passing is rare. If kids want to communicate during school they simply just shoot each other a text message. Also, today if someone is to leave the house, making a phone call is easy. With a quick dial on a cellphone people can make a call at any time. Cellphones have not only changed the way we communicate but they have changed our safety. Texting and driving has become common and has caused many deaths in the United States. It was reported in 2005 that cellphone distraction causes 2,600 deaths and 330,000 injuries in the United States every year. Another safety issue with cellphones is privacy. Say someone’s at an airport, or on the bus. Several people are on their cellphones, some talking business, and others talking about personal information. Any information shared has now become available to anyone else who might have been around to hear their phone call. Others may now know their address, information about their family, or financial records. Before cellphones life were more safe. Before cell phones people didn’t have to constantly worry about someone overhearing their conversation. Also people didn’t have to worry about others driving them off the road because of the careless mistake of texting while driving. The cellphone is loved by many and hated by the few for ruining society. Although cellphones have changed society I have a hard time imagining my life without one. Cellphones have had a major impact on our lives and have vastly changed our manners, the way we communicate and our safety. Many of these changes are apparent, while others we may not even be aware of.

Does the United States Government invest too much money in national Research Paper

Does the United States Government invest too much money in national security - Research Paper Example The US was also said to have provided the Transitional Federal Government with small arms and munitions and paid for some of their training in 2009, although US forces have not been involved directly in training troops. US assistance has been coursed through the Department of State and about US$40,000 has been allocated for Somalia in 2010 through the International Military Education Training (IMET) program. Others were enumerated as funds for Non-proliferation, Anti-terrorism, Demining and Related Programmes - Humanitarian Demining with $1.4 million in 2001, $1.2 million in 2002 and $450,000 in 2003 (Jane's Information Group). In 2008, about $754,000 has been allocated and $2 million was requested for 2010. The budget and concern for Somalia emerged from the star of the civil war in Somalia when lack of strong leadership led for many Somali to join pirates. The lack of formal Somali defense also provided threat to Somali territories making them susceptible to trawlers. The funding provided by the US and other Western countries to Somalia and other African nations are used to maintain state stability, sustain and improve international relations, battle organized crimes, proliferation and procurement of security devices and to counter terrorism and insurgency in the region and the locality The aids provided for Somalia include infrastructure to address a 24/7 aerial relocation and medical evacuation capability within Somalia and improve security in order to sustain the United Nations operation and security of the environment

AI Week 13 Eye moving DB 153 Essay Example | Topics and Well Written Essays - 250 words

AI Week 13 Eye moving DB 153 - Essay Example Various governments have limited fiscal budgets and pressure (Feldstein, 2011). This is because it has to take care for the health of the aging population. Shifting the cost to the public only increases the level of taxes and affects the finances of various households. Such costs could be unsustainable for the lower and average income earners. There are disparities in the level of income for different household individuals. The public consists of a majority of average income earners. If the cost of health care for high-risk employees shifts to the public, then high-income earners should make the biggest contribution. Genetic factors cause most affected employees to inherit some chronic diseases. Such health care plans make the employees feel some form of discrimination from their employers. Employers should treat all the employees with equality regardless of their health background. The employers should instead make health care policies affordable for all the employees. Relevant authorities need to regulate insurance companies in the creation of their health care policies (Feldstein, 2011). The regulations should require the companies to provide insurance covers at normal charges. The employees should seek routine checkups from their healthcare providers to put their condition under control. The employers should avoid any form of discrimination in the determination of the health benefits. Shifting the public health care cost to the public could be unfair for both low and average income

Reading Standard for Foundational SKills Assignment

Reading Standard for Foundational SKills - Assignment Example However, for the younger students such as the one in pre-kindergarten, the list of objectives should be way smaller with only one or two items to be assessed by the teachers as they are still very young will smaller ability to understand and shorter memory span. The above mentioned tools in the checklist cannot be appropriate for assessment of children from birth to pre-kindergarten as they are very young and cannot understand what is being tested. However it is appropriate for those from kindergarten to grade 3 as they also hold similar learning objectives as the ones discussed above in the check list. For the children between births to pre-kindergarten, they should have their own set of simpler and way shorter learning objectives which would lead to shorter assessment and check lists for the teachers to examine. This as explained above is because of their short memory span as well as ability to understand which is still developing. Most of the assessment tools for such children are just repetitive sounds and music among other simpler

Microsoft Access Database Assignment Example | Topics and Well Written Essays - 500 words

Microsoft Access Database - Assignment Example Each company is known to produce different products and at the same time it can produce the same products but different brands. For instance, Delmonte Company is known to produce soft drinks as its major product among other items. Incase this company fails to supply; other companies are there to take over the tender and supply the same products but different brands. Other outstanding Companies are Cocacola, Nuvita and Afia. Cocacola Company produces softdrinks that serve as energy drinks and therefore makes it to be unique with other competing companies; Nuvita produces soft drinks with different brand and is known for its high quality products at affordable prices; Afia Company produces softdrinks rich in vitamins as compared to others. These all vendors have the same thing in common as shown by their variety of products produced by each. Both Afia and Delmonte produce the same products and each supplies the restaurant with their soft drinks. The slight differences between these two companies are their products brands, therefore their drinks serve the same

Coursework Example | Topics and Well Written Essays - 1250 words - 1

Coursework Example The company is involved in geological exploration, storage as well as processing and marketing of hydrocarbons. Demand and supply factors As the chosen company operates in the oil and gas sector the demand side factors that can affect sales and the profitability of the company include weather, demographics, economic growth, fuel consumption, storage and the exports potential. From the supply side, the factors which can affect the sales are capacity of the pipeline, storage, gas drilling, issues on technical grounds and imports. The demand follows the cyclical patterns. It also depends on the time and season factors. The demand for the products rises during the hottest months while the demand takes the declining curve during the winter months ((EIA, 2008). The price of the natural gas affects those consumers who have the potential to switch to the fuel of their dependence. The demand that is created by the retail consumers will get affected by the price of electricity. Storage of the produced products is difficult for the companies in this sector and so excess supply cause a fall in the price level. The price is generally set at the equilibrium level as there are several competitors present in the market. Technological advancements can also play a role in the demand of natural gas. The appliances which can be operated through electricity can now be operated through natural gas and this has caused the demand for the product to shoot up. The other barriers that can impact upon the supply of natural gas are availability of skilled labor and availability of well developed systems of delivery. The financial environment can also affect the supply of natural gas both off-shore and on-shore ((Natural Gas, n.d.). Market Structure The consumers can now enjoy the luxury of choice and competition. The price mechanism is beyond the regulations of the government. The price is set by the market by following the usual demand and supply factors. These factors play its role in se tting the price at the equilibrium level. A straight forward market structure characterized the market for natural gas prior to deregulation and unbundling of pipeline. Bundled products are offered by the less developed countries and they play their role in supplying the products to the end users. Marketers serve the purpose of mobilizing the natural gas to end users. (Natural gas, n.d.). The increased liquidity in the market has called for the emergence of non-contract LNG market. The producer owns the gas at well head and sells to the marketers, and less developed countries and even sometimes to the end users. The market faces a serious constraint as it cannot react to the usual changes in demand and supply and requires sufficient time before the adjustment process takes place ((Soligo and Jaffe, p.2, 2004). Requirements to compete in the market The companies that operate in this sector enjoy monopoly power and that is the reason why they tend to be more profitable. The main requi site for the organizations to maintain the profitable position is to avoid preferential as well as discriminatory service. Inefficient investments in other sectors can be avoided. The strategies of unfair pricing would also not help the company to serve the purpose. There is no substitute to quality and so measures to maintain the quality of the products should be undertaken. The