A quantidade X de chumbo tetraetílico, em mL por galão, adicionada a certo combustível é uma variável aleatória cuja função de densidade de probabilidade é dada a seguir.

!$ f(x)=\dfrac{4-x}{8}, \, se \, 0 \le x < 4 !$

!$ f(x)=0, \, se \, x \ge 4 \, ou \, se \, x <0 !$

Considerando essas informações, julgue o próximo item.

Caso uma amostra do referido combustível seja coletada aleatoriamente, a probabilidade de essa amostra conter até 2 mL por galão de chumbo tetraetílico será superior a 0,7.

A variância amostral dos diâmetros desses anéis é inferior a 2.

O departamento de recursos humanos de uma empresa recebe diariamente uma quantidade aleatória X de pedidos de auxíliotransporte.

Considerando a tabela acima, que mostra a distribuição de probabilidade de X, julgue o item seguinte.

O número médio de pedidos é superior a 1,5.

A quantidade X de chumbo tetraetílico, em mL por galão, adicionada a certo combustível é uma variável aleatória cuja função de densidade de probabilidade é dada a seguir.

!$ f(x)=\dfrac{4-x}{8}, \, se \, 0 \le x < 4 !$

!$ f(x)=0, \, se \, x \ge 4 \, ou \, se \, x <0 !$

Considerando essas informações, julgue o próximo item.

A quantidade média de X é inferior a 1,5 mL por galão.

A quantidade X de chumbo tetraetílico, em mL por galão, adicionada a certo combustível é uma variável aleatória cuja função de densidade de probabilidade é dada a seguir.

!$ f(x)=\dfrac{4-x}{8}, \, se \, 0 \le x < 4 !$

!$ f(x)=0, \, se \, x \ge 4 \, ou \, se \, x <0 !$

Considerando essas informações, julgue o próximo item.

A probabilidade de se observar o evento X = 0 é igual a 0,5.

Considere que a vazão V de um oleoduto seja uma variável aleatória que siga uma distribuição normal com média igual a 1.000 m³ por dia e desvio-padrão igual a 500 m³ por dia. Nessa situação, julgue o item subseqüente.

A quantidade !$ \dfrac{V-1.000}{100} !$ m³ segue uma distribuição normal com média zero e desvio-padrão igual a 5.

O número de pedidos X é igual a 1 com probabilidade igual a 0,6.

A média amostral e a mediana amostral dos diâmetros desses anéis são, respectivamente, iguais a 80 mm e 79 mm.

Broken windows, broken business

The book Broken Windows, Broken Business, by Michael Levine, was inspired by an article entitled Broken Windows, by criminologists James Q. Wilson and George L. Kelling in the March, 1982 issue of Atlantic Monthly. Wilson and Kelling suggested that when laws against minor crimes, such as graffiti and turnstile1 jumping, are enforced, and broken windows are promptly repaired, major crime rates will decline.

When Rudolph Giuliani became mayor of New York City in 1994, he worked with police commissioner William Bratton to implement a “zero tolerance” broken windows policy. Graffiti was promptly cleaned up on subway cars. Turnstile jumping wasn’t tolerated. Laws against petty crimes were enforced. Those guys who’d take advantage of traffic jams or red lights to jump in front of cars with a squeegee2, quickly cleaning the windshield and begging for money were arrested on the grounds of jaywalking316 ! A good many of them were carrying weapons. Over the following few years, the number of murders, assaults, robberies and other violent crimes went down dramatically. It was made clear that the good guys would be in charge there, not wrongdoers.

Levine says the same principle applies to businesses. Business owners and their employees must become fanatics in attending to the details of presenting outstanding customer service and in the image presented by the business to inspire customer confidence and loyalty. The broken windows theory is all about the unmistakable power of perception, about what people see and the conclusions they draw from it. In business, perception is even more critical. The way a customer (or potential customer) perceives your business is a crucial element in your success or failure. Make one mistake, have one rude employee, let that customer walk away with a negative experience one time, and you are inviting disaster. Small things make a huge difference in business. The messy condiment area at a fast food restaurant may lead consumers to believe the company as a whole doesn’t care about cleanliness, and therefore the food itself might be in question. Indifferent help at the counter in an upscale clothing store — even if just one clerk — can signal to the consumer that perhaps standards here aren’t as high as they might be (or used to be). An employee at the gas station who wears a T-shirt with an offensive slogan can certainly cause some customers to switch brands of gasoline and lose an enormous company those customers for life.

Mystery shoppers should be regularly employed to learn whether customers are having a positive experience dealing with a company. Candidates for mystery shoppers to recruit include customers who already complain about their experiences with the company.

It is critical that the right kind of people (those who enjoy dealing with people) be hired for customer contact positions. Employees exhibiting an attitude of “a smile isn’t in my job description” must be told that a smile certainly is required, and to find other employment if they can’t fulfill the required behavior.

The worst business scenario is “broken window hubris4”. Examples are Kmart and Enron. A company suffers from broken window hubris when management thinks the business is so successful that it’s no longer important to please customers.

Internet: <www.profitadvisors.com> (adapted).

¹turnstile – a narrow gate at the entrance of something, with metal bars that move in a circle so that only one person at a time can go through.

²squeegee – an object used for cleaning windows, consisting of a short handle with a rubber blade.

³jaywalking – a dangerous or illegal way of crossing a street at a place where cars do not usually stop.

⁴hubris – a very proud way of talking or behaving that offends people.

It can be inferred from the text that

some people were used to riding free in subways in New York.

PETROBRAS is the world’s eighth most respected company

PETROBRAS has skyrocketed to the 8th place among the world’s most respected corporations, up from the 83rd position. The ranking was announced by the Reputation Institute (RI), a private advisory and research company headquartered in New York with representation in upwards of 20 countries.

The survey, carried out for the tenth year in a row, lists the world’s 600 biggest companies. The Reputation Institute created a research model to measure the perceptions of esteem, trust, respect, and admiration consumers have of companies. RI interviewed upwards of 60,000 people, from January to February 2007, in 29 countries. In the survey it announced in May, 2007, RI highlights PETROBRAS’ leap to 82.19 points in 2007, up from 73.99 in 2006, the biggest surge registered among the top 8. The company rose 75 positions to rank ahead of companies of the likes of Michelin, UPS, the Swatch Group, Honda, and Kraft Foods. PETROBRAS also leads the pack among energy companies. The segment’s runner-up was Russian Gazprom-neft, which was rated 28th.

The same international rating singles PETROBRAS out as the Brazilian leader. Twenty Brazilian companies participated in the survey, four of which rated among the top 50 led by PETROBRAS. In the 2006 survey, no Brazilian companies appeared amid the world’s 50 most respected corporations.

Internet: <www.petrobras.com.br> (adapted).

Based on the text above, judge the following item.

According to RI’s ranking, an 8.20-point difference in relation to 2006 brought PETROBRAS to the top 8 in 2007.