CISC 102 Lecture 3: Sets P2

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17 Oct 2016

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If a and b have no elements in common, then we say that they are disjoint. Using subset notation we can say that if a and b are disjoint, then a b and b a. However, if a b and b a then a and b may not be disjoint. For example, they may share some elements with each other, but also contain elements that are not similar. All sets under in any application of set theory are assumed to belong to some fixed large set, called the universal set. The universal set is a superset of every set. A set with no elements is called the empty or null set. The empty set is a subset of every set. Both p and q have to be true for the compound proposition p and q to be true p(cid:1166)q (p or q)

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You are doing a walk-through of the credit and collections function to get an idea of what internal controls exist and where there might be weaknesses. Then, after you finish, you or another member of the audit team will be testing the system to determine whether the internal controls actually exist and actually work as you have been told. In the meantime, keep your eyes, ears, and mind open for any weaknesses in internal control.

The department head of the credit and collections department is telling you how things work in the department. "Jenny, here, receives the mail and distributes it to the various collectors. They each open their own mail. There is a lot of correspondence going back and forth to and from customers, so it is easier if each collector just handles her own mail." It is easy for Jenny to distribute the mail because most of the letters are addressed to a specific individual.

You watch as one of the individuals opens the mail and handles the items inside. Many of the items are disputes-the customer says the items billed were not ordered, or, if ordered, were not received. Every such letter results in the disputed bill being written off. As the department head explains, the vice president of sales told him, a few years ago, that too many customers were complaining that the credit department was too tough on them, so he had decided that rather than have any more complaints, every such bill would be written off. The procedure is that the collector initiates a form, called a write-off form, to write off a particular amount from a customer's balance. In the explanation block, the collector simply writes "customer dispute." This form is signed by the collector, sent to accounting, and accounting processes the forms each Wednesday. There are so many letters with so many disputes that the department has a monthly competition for the most unusual letters, which are tacked up on a bulletin board. All the rest of the dispute letters are thrown away as soon as the collector has filled out the write-off form.

Collectors also receive checks in the mail. These are payments from customers whose accounts are wholly or partly overdue. As one of the collectors explains, they each receive a print-out once a month, so if the customer sends in a payment, there is no way for the collector to find out about it before the next month's print-out arrives unless the collector receives the payment. Most of the collectors process dozens of payments each month. They make whatever notations they need on the monthly print-out, prepare a deposit ticket, send the department's runner to the bank each Friday (collections are accumulated until Friday, with the customers' payments being held in an otherwise empty desk drawer until then), and send the receipted deposit ticket on to the department which records collections of cash. The credit and collections department also sends a listing of which customers to credit for having paid all or part of their balances.

Near the end of each fiscal quarter, the corporate controller gets a preliminary set of financial statements, and then he tells the department head by telephone how much the department is allowed to write off in bad debts. Thus, the company writes off bad debts only in the third month of each fiscal quarter. "Why does he tell you by telephone?" you ask of the credit and collections manager. "He doesn't want any written record of it," is the reply.

You are interested in how the department decides which customer balances to write off as uncollectible and which to leave on the books. "We write off the oldest ones, up to the amount of what we have been told we can write off," says the credit and collections manager. "That way, our percentage of bad debts always comes out pretty much in line with what we have done before, and the auditors have always been satisfied with it. They had read some academic articles from some people who recommended using time-series analysis to see if the numbers were correct, so they test the accounts receivable account and satisfy themselves that the sales and receivables are real, but they always test the write-offs and bad debts expense simply by using the time-series analysis recommended by the accountants with those fancy doctorates. Go ask the guy who ran the audit last year."

You inspect the process by which customer payments are received the regular way, which is done in a different department. The company has a special Post Office box set up. Twice a day, some one person from maintenance goes to the Post Office to pick up the mail, including the customer payments received at this special Post Office box. It is not always the same person from maintenance who goes to the Post Office; whoever is available when the department head looks around is typically the one who is sent.

When the person returns from the Post Office, he brings a bunch of mail to the cash receipts department, where the mail is opened and customers' checks are paperclipped to the envelopes they came in. One of the goals of the cash receipts department is to get the customer payments deposited promptly, so after all the checks are paper-clipped, someone from the department goes to the bank, fills out a whole bunch of deposit slips, deposits those checks, and comes back to the department with those receipted deposit slips. Then the department members try to figure out which customer paid which amounts. They are helped by the routing number on the checks, but those routing numbers represent banks, not customers, and multiple customers use the same banks. Consequently, they refer to a listing of routing numbers to identify the banks, then to a listing of banks to see which customers use those banks, and then to another copy of the same monthly print-out used in credit and collections to figure out which of the customers who use that bank must have paid that particular amount. If they cannot make a good guess, they call some of the customers to ask if they are the ones who paid the amount. Once they think they know who paid the amount, they generate a journal entry to debit cash and credit the customer's account; the credit to the customer's account is automatically also a credit to accounts receivable. Since they have a copy of the monthly printout of accounts receivable, when a customer's payment is not for the full amount of an invoice, they just go ahead and adjust that customer's account so the full amount of the invoice is taken off the customer's account. They say they are creating a lot of goodwill with customers that way.

a. What internal control weaknesses do you see in this system?

b. What are the potential effects of these weaknesses?

c. What do you recommend instead (that is, if you have such a recommendation)?

skycricket458

What valuable company is nobody building? This question is harder than it looks, because your company could create a lot of value without becoming very valuable itself. Creating value isn't enough -- you also need to capture some of the value you create. This means that even very big businesses can be bad businesses. For example, U.S. airline companies serve millions of passengers and create hundreds of billions of dollars of value each year. But in 2012, when the average airfare each way was $178, the airlines made only 37 cents per passenger trip. Compare them to Google, which creates less value but captures far more. Google brought in $50 billion in 2012 (versus $160 billion for the airlines), but it kept 21% of those revenues as profits -- more than 100 times the airline industry's profit margin that year. Google makes so much money that it is now worth three times more than every U.S. airline combined. The airlines compete with each other, but Google stands alone. Economists use two simplified models to explain the difference: perfect competition and monopoly. "Perfect competition" is considered both the ideal and the default state in Economics 101. So-called perfectly competitive markets achieve equilibrium when producer supply meets consumer demand. Every firm in a competitive market is undifferentiated and sells the same homogeneous products. Since no firm has any market power, they must all sell at whatever price the market determines. If there is money to be made, new firms will enter the market, increase supply, drive prices down and thereby eliminate the profits that attracted them in the first place. If too many firms enter the market, they'll suffer losses, some will fold, and prices will rise back to sustainable levels. Under perfect competition, in the long run no company makes an economic profit. The opposite of perfect competition is monopoly. Whereas a competitive firm must sell at the market price, a monopoly owns its market, so it can set its own prices. Since it has no competition, it produces at the quantity and price combination that maximizes its profits. To an economist, every monopoly looks the same, whether it deviously eliminates rivals, secures a license from the state or innovates its way to the top. I'm not interested in illegal bullies or government favorites: By "monopoly," I mean the kind of company that is so good at what it does that no other firm can offer a close substitute. Google is a good example of a company that went from 0 to 1: It hasn't competed in search since the early 2000s, when it definitively distanced itself from Microsoft and Yahoo! Americans mythologize competition and credit it with saving us from socialist bread lines. Actually, capitalism and competition are opposites. Capitalism is premised on the accumulation of capital, but under perfect competition, all profits get competed away. The lesson for entrepreneurs is clear: If you want to create and capture lasting value, don't build an undifferentiated commodity business. How much of the world is actually monopolistic? How much is truly competitive? It is hard to say because our common conversation about these matters is so confused. To the outside observer, all businesses can seem reasonably alike, so it is easy to perceive only small differences between them. But the reality is much more binary than that. There is an enormous difference between perfect competition and monopoly, and most businesses are much closer to one extreme than we commonly realize. The confusion comes from a universal bias for describing market conditions in self-serving ways: Both monopolists and competitors are incentivized to bend the truth. Monopolists lie to protect themselves. They know that bragging about their great monopoly invites being audited, scrutinized and attacked. Since they very much want their monopoly profits to continue unmolested, they tend to do whatever they can to conceal their monopoly -- usually by exaggerating the power of their (nonexistent) competition. Think about how Google talks about its business. It certainly doesn't claim to be a monopoly. But is it one? Well, it depends: a monopoly in what? Let's say that Google is primarily a search engine. As of May 2014, it owns about 68% of the search market. (Its closest competitors, Microsoft and Yahoo!, have about 19% and 10%, respectively.) If that doesn't seem dominant enough, consider the fact that the word "google" is now an official entry in the Oxford English Dictionary -- as a verb. Don't hold your breath waiting for that to happen to Bing. But suppose we say that Google is primarily an advertising company. That changes things. The U.S. search-engine advertising market is $17 billion annually. Online advertising is $37 billion annually. The entire U.S. advertising market is $150 billion. And global advertising is a $495 billion market. So even if Google completely monopolized U.S. search-engine advertising, it would own just 3.4% of the global advertising market. From this angle, Google looks like a small player in a competitive world. What if we frame Google as a multifaceted technology company instead? This seems reasonable enough; in addition to its search engine, Google makes dozens of other software products, not to mention robotic cars, Android phones and wearable computers. But 95% of Google's revenue comes from search advertising; its other products generated just $2.35 billion in 2012 and its consumer-tech products a mere fraction of that. Since consumer tech is a $964 billion market globally, Google owns less than 0.24% of it -- a far cry from relevance, let alone monopoly. Framing itself as just another tech company allows Google to escape all sorts of unwanted attention. Non-monopolists tell the opposite lie: "We're in a league of our own." Entrepreneurs are always biased to understate the scale of competition, but that is the biggest mistake a startup can make. The fatal temptation is to describe your market extremely narrowly so that you dominate it by definition. Suppose you want to start a restaurant in Palo Alto that serves British food. "No one else is doing it," you might reason. "We'll own the entire market." But that is only true if the relevant market is the market for British food specifically. What if the actual market is the Palo Alto restaurant market in general? And what if all the restaurants in nearby towns are part of the relevant market as well? These are hard questions, but the bigger problem is that you have an incentive not to ask them at all. When you hear that most new restaurants fail within one or two years, your instinct will be to come up with a story about how yours is different. You'll spend time trying to convince people that you are exceptional instead of seriously considering whether that is true. It would be better to pause and consider whether there are people in Palo Alto who would rather eat British food above all else. They may well not exist. In 2001, my co-workers at PayPal and I would often get lunch on Castro Street in Mountain View, Calif. We had our pick of restaurants, starting with obvious categories like Indian, sushi and burgers. There were more options once we settled on a type: North Indian or South Indian, cheaper or fancier, and so on. In contrast to the competitive local restaurant market, PayPal was then the only email-based payments company in the world. We employed fewer people than the restaurants on Castro Street did, but our business was much more valuable than all those restaurants combined. Starting a new South Indian restaurant is a really hard way to make money. If you lose sight of competitive reality and focus on trivial differentiating factors -- maybe you think your naan is superior because of your great-grandmother's recipe -- your business is unlikely to survive. The problem with a competitive business goes beyond lack of profits. Imagine you're running one of those restaurants in Mountain View. You're not that different from dozens of your competitors, so you've got to fight hard to survive. If you offer affordable food with low margins, you can probably pay employees only minimum wage. And you'll need to squeeze out every efficiency: That is why small restaurants put Grandma to work at the register and make the kids wash dishes in the back. A monopoly like Google is different. Since it doesn't have to worry about competing with anyone, it has wider latitude to care about its workers, its products and its impact on the wider world. Google's motto -- "Don't be evil" -- is in part a branding ploy, but it is also characteristic of a kind of business that is successful enough to take ethics seriously without jeopardizing its own existence. In business, money is either an important thing or it is everything. Monopolists can afford to think about things other than making money; non-monopolists can't. In perfect competition, a business is so focused on today's margins that it can't possibly plan for a long-term future. Only one thing can allow a business to transcend the daily brute struggle for survival: monopoly profits. So a monopoly is good for everyone on the inside, but what about everyone on the outside? Do outsize profits come at the expense of the rest of society? Actually, yes: Profits come out of customers' wallets, and monopolies deserve their bad reputation -- but only in a world where nothing changes. In a static world, a monopolist is just a rent collector. If you corner the market for something, you can jack up the price; others will have no choice but to buy from you. Think of the famous board game: Deeds are shuffled around from player to player, but the board never changes. There is no way to win by inventing a better kind of real-estate development. The relative values of the properties are fixed for all time, so all you can do is try to buy them up. But the world we live in is dynamic: We can invent new and better things. Creative monopolists give customers more choices by adding entirely new categories of abundance to the world. Creative monopolies aren't just good for the rest of society; they're powerful engines for making it better. Even the government knows this: That is why one of its departments works hard to create monopolies (by granting patents to new inventions) even though another part hunts them down (by prosecuting antitrust cases). It is possible to question whether anyone should really be awarded a monopoly simply for having been the first to think of something like a mobile software design. But something like Apple's monopoly profits from designing, producing and marketing the iPhone were clearly the reward for creating greater abundance, not artificial scarcity: Customers were happy to finally have the choice of paying high prices to get a smartphone that actually works. The dynamism of new monopolies itself explains why old monopolies don't strangle innovation. With Apple's iOS at the forefront, the rise of mobile computing has dramatically reduced Microsoft's decadeslong operating system dominance. Before that, IBM's hardware monopoly of the 1960s and '70s was overtaken by Microsoft's software monopoly. AT&T had a monopoly on telephone service for most of the 20th century, but now anyone can get a cheap cellphone plan from any number of providers. If the tendency of monopoly businesses was to hold back progress, they would be dangerous, and we'd be right to oppose them. But the history of progress is a history of better monopoly businesses replacing incumbents. Monopolies drive progress because the promise of years or even decades of monopoly profits provides a powerful incentive to innovate. Then monopolies can keep innovating because profits enable them to make the long-term plans and finance the ambitious research projects that firms locked in competition can't dream of. So why are economists obsessed with competition as an ideal state? It is a relic of history. Economists copied their mathematics from the work of 19th-century physicists: They see individuals and businesses as interchangeable atoms, not as unique creators. Their theories describe an equilibrium state of perfect competition because that is what's easy to model, not because it represents the best of business. But the long-run equilibrium predicted by 19th-century physics was a state in which all energy is evenly distributed and everything comes to rest -- also known as the heat death of the universe. Whatever your views on thermodynamics, it is a powerful metaphor. In business, equilibrium means stasis, and stasis means death. If your industry is in a competitive equilibrium, the death of your business won't matter to the world; some other undifferentiated competitor will always be ready to take your place. Perfect equilibrium may describe the void that is most of the universe. It may even characterize many businesses. But every new creation takes place far from equilibrium. In the real world outside economic theory, every business is successful exactly to the extent that it does something others cannot. Monopoly is therefore not a pathology or an exception. Monopoly is the condition of every successful business. Tolstoy famously opens "Anna Karenina" by observing: "All happy families are alike; each unhappy family is unhappy in its own way." Business is the opposite. All happy companies are different: Each one earns a monopoly by solving a unique problem. All failed companies are the same: They failed to escape competition.

According to the article above by Peter Thiel do you think perfect competition is best for the economy and for consumers? Why or why not? What does Peter Thiel think about perfect competition versus monopolies?

Seperation lab: Will rate question

Separation lab - will choose best answer

Seperation lab: will choose best answer

Separation of a Mixture Laboratory

In this experiment we will separate the different components of a mixture made up of sand (SiO2) and sodium chloride (NaCl, commonly known as salt). Both of these compounds are solid white crystals, so it is difficult to tell them apart with the naked eye. However, each component exhibits different physical properties that can be used to separate one from the other. There are several physical separation techniques that can be used to determine the percent composition of the original mixture.

Materials & Apparatus:

Sand/salt mixture provided in your Lab Kit

2 - Erlenmeyer Flasks

Scale

Water

Graduated Cylinder

Background:

It is important to know how to separate mixtures because many reactions carried out in the laboratory produce mixtures of different compounds. It is often necessary to separate the components of these mixtures, which can be done using several techniques. We will explore a few of these techniques: sublimation, filtration, evaporation and decantation.

Sublimation is the process of a substance passing from the solid to the gaseous state without first passing through the liquid state. Not all substances possess this characteristic. In fact, most substances to NOT sublime under normal conditions, but must be placed under low pressure and low temperature. Ammonium chloride (NH4Cl) and iodine (I2) are both substances that do sublime under normal conditions.

Filtration is the process used to separate the components of a mixture of solid substances that differ in solubility in a certain solvent. You can separate a mixture of solid substances by adding a liquid to the original mixture in which only some of the components of the mixture will dissolve. The resulting mixture, which contains both the dissolved and undissolved substances, is then poured through a filter paper--a porous paper that allows liquids to pass through while retaining any solids. The liquid that has passed through the filter paper is called the filtrate; the solid on the paper is the residue.

Evaporation can also be used to separate the solvent from the solution. A solution can be slowly heated in an Erlenmeyer flask, and the solute will remain after the solvent has evaporated.

Decantation is the process of separating a liquid from a solid (sediment) by gently pouring the liquid from the solid so as not to disturb the solid.

For this experiment, a practical plan is as follows: First combine the solid mixture of the two compounds, sodium chloride (NaCl) and sand (SiO2), with water. This will dissolve the sodium chloride. The sand will not dissolve into the water. We will "filter" the entire mixture, which allows the water in which the sodium chloride is dissolved to pass through, but not the sand. We will now have separated the sodium chloride and the sand. Then, we must evaporate off the water so that we weigh only the two original solids and not the water we added.

Procedure:

(NOTE: Do NOT dispose of any part of your lab until you are 100% positive you do not need it again. It is good practice to keep all parts of your lab until you are finished.)

Record the letter (A, B, C, or D) of your mixture (on the bag contents label) on the line above Data Table 1 below.

Obtain an Erlenmeyer flask [label it 1] and weigh and record the mass.

Add the entire contents of your unknown mixture bag to the flask and weigh and record the mass of the Erlenmeyer flask and the mixture.

Add 10 mL of water (preferably distilled) to the solid in the Erlenmeyer flask [Erlenmeyer flask 1] and stir gently for 5 minutes.

Weigh a new clean, dry Erlenmeyer flask [Erlenmeyer flask 2].

Decant the liquid from Erlenmeyer flask 1 into Erlenmeyer flask 2. This may work better if you place a utensil against the lip of the pouring flask to encourage a slow steady stream of liquid into the second flask.

Add another 10 mL of water to the solid in Erlenmeyer flask 1, stir for 1-2 minutes, and decant this liquid into the Erlenmeyer flask 2 as before.

Repeat with still another 10 mL of water. This process extracts (dissolves) the soluble sodium chloride from the insoluble sand.

Allow the two flasks to dry. Let them dry until the sand appears dry and freely moves when you shake the Erlenmeyer flask a little and the sodium chloride looks dry.

To speed up the process, you can heat the flasks slowly over a burner set on low on your stove top or in the oven (set at 125-200ËF). I would suggest heating it on top of another pan (NOT nonstick coated) Use a low setting and watch closely as you donât want it to boil over.

Allow the Erlenmeyer flasks to cool to room temperature (if they were heated) and weigh the Erlenmeyer flasks and their contents separately. Record their masses in the appropriate sections of the table.

To ensure that there is no water remaining, heat for another 5-10 minutes oven or 1-2 minutes on the stove. Allow to cool to room temperature and reweigh the Erlenmeyer flask. If it is within 0.3 g of your initial weighing you can stop. If the second weighing is not within 0.3 g of your initial weighing, reheat again, cool, and reweigh. The difference between this mass and the mass of the empty Erlenmeyer flask is the mass of NaCl.

Unknown Mixture Label (A, B, C, or D) ___________

Data Table 1

Measure or calculate and record the following (in grams):
mass of the empty Erlenmeyer flask 1:
mass of the Erlenmeyer flask 1 plus the mixture sample:
mass of the mixture sample:
mass of the Erlenmeyer flask 1 and the remaining contents after drying of sand:
mass of Erlenmeyer flask 1 and dry sand (2nd weighing)
Subtract (a) from (e) to obtain the mass of sand in the sample:
Measure or calculate and record the following (in grams):
mass of an empty Erlenmeyer flask 2:
mass of Erlenmeyer flask 2 and dry NaCl (1st weighing)
mass of Erlenmeyer flask 2 and dry NaCl (2nd weighing)
mass of Erlenmeyer flask 2 and dry NaCl (3rd weighing) if necessary
measured mass of dry NaCl:

Assignment Questions (all work must be shown for all calculations):

Using the results of your lab, complete all the questions below.

Upload one picture that is representative of your experiment with this report to the appropriate D2L Brightspace Assignments folder.

Complete Data Table 1 located in the Procedure. Make sure to include all your work for all the calculations performed.

The amount of sodium chloride in the original mixture may also be determined indirectly by subtracting the SiO2 mass from the initial sample mass. Calculate the expected mass of NaCl using this method.

Calculate the percent difference of NaCl (Note: This is not % Error, but it is a similar calculation. This is an error calculation that checks precision between the results of the two methods from the following equation: (Note: the unit for this calculation is â% differenceâ)

% difference=measured mass-mass by subtractionmass by subtraction x 100

What is the mass percent of each component in your mixture: SiO2, and NaCl? (Note: the units for this calculation are â% SiO2â and â% NaClâ)

mass percent=mass of componenttotal mass of sample x 100

Error Analysis: Was your % difference from Assignment Question 4 within 10%? Why or why not? Did your two mass percentages in Assignment Question 5 add up to 100%? Why or why not? What were your biggest sources of error in this experiment? What would you do differently if you were to repeat this experiment? Explain.

What type of properties (physical or chemical) are we using to separate the mixture in this laboratory. Explain your answer.

A mixture is found to contain 0.69 g SiO2, 1.05 g of cellulose, and 2.17 g of calcium carbonate. What is the mass percentage of SiO2 in this mixture?

Assume you have a mixture of NH4Cl, sand, and salt and access to a regular chemistry laboratory. How would you separate the three?Write out what your procedure would be in numbered steps. Please research the answer to this question and properly cite your source. It is alright to research using the internet. However, Wikipedia, Yahoo Answers, Ask.com, and other non-scientific sources cannot be used.

CISC 102 Lecture 3: Sets P2

CISC 102 Full Course Notes

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