Chapter 13, Level 1 Self-Quiz: A

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Read the following passage. Identify the correct sample and population.

A random study of 6000 urban public high school seniors throughout the United States has confirmed what many have long suspected. The students were given the same verbal, mathematical, perceptual, and manual dexterity test that was given 20 years ago to high school seniors. The Bincaid-Forbush test had not been used for over 15 years, so the researchers thought that it could be a good way of comparing the results of the preceding generation (many of whom are probably the parents of todays seniors) with the current crop of students. As expected, verbal and math scores have declined by 20% in todays students.

Surprisingly, the perceptual and manual dexterity scores of today's students are 34% higher than their parents' generation. The researchers speculate that the rise of computers and arcade video games can explain both results. They hypothesize that verbal and math skills have deteriorated because video games require very little reading or calculating. However, these games require superior perceptual and manual dexterity skills, and thus give today's students much more exposure to this kind of skill development.

Sample: 6000 urban high school students throughout the United States; Population: All U.S. high school seniors

Sample: 6000 urban public high school students in two counties in the United States; Population: All U.S. public high school seniors

Sample: 6000 urban public high school seniors throughout the United States; Population: All U.S. high school seniors

Sample: 6000 urban public high school students throughout the United States; Population: All U.S. high school seniors

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Read the following passage. Identify the sample size, and whether or not the sample is representative of the population referred to in the conclusion.

A random study of 6000 urban public high school seniors throughout the United States has confirmed what many have long suspected. The students were given the same verbal, mathematical, perceptual, and manual dexterity test that was given 20 years ago to high school seniors. The Bincaid-Forbush test had not been used for over 15 years, so the researchers thought that it could be a good way of comparing the results of the preceding generation (many of whom are probably the parents of today's seniors) with the current crop of students. As expected, verbal and math scores have declined by 20% in todays students.

Surprisingly, the perceptual and manual dexterity scores of today's students are 34% higher than their parents' generation. The researchers speculate that the rise of computers and arcade video games can explain both results. They hypothesize that verbal and math skills have deteriorated because video games require very little reading or calculating. However, these games require superior perceptual and manual dexterity skills, and thus give today's students much more exposure to this kind of skill development.

Sample size: The sample is small and taken from pre-selected parts of the United States. This decreases the likelihood that the sample is representative of the population.

Sample size: The sample is large but taken from pre-selected parts of the United States. This decreases the likelihood that the sample is representative of the population.

Sample size: The sample is large and taken from throughout the United States. This raises the likelihood that the sample is representative of the population.

Sample size: The sample is not large and taken from throughout the United States. This decreases the likelihood that the sample is not representative of the population.

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Read the following passage. Determine potential bias and whether or not the sample is random. A random study of 6000 urban public high school seniors throughout the United States has confirmed what many have long suspected. The students were given the same verbal, mathematical, perceptual, and manual dexterity test that was given 20 years ago to high school seniors. The Bincaid-Forbush test had not been used for over 15 years, so the researchers thought that it could be a good way of comparing the results of the preceding generation (many of whom are probably the parents of today's seniors) with the current crop of students. As expected, verbal and math scores have declined by 20% in today's students.

Surprisingly, the perceptual and manual dexterity scores of todays students are 34% higher than their parents' generation. The researchers speculate that the rise of computers and arcade video games can explain both results. They hypothesize that verbal and math skills have deteriorated because video games require very little reading or calculating. However, these games require superior perceptual and manual dexterity skills, and thus give today's students much more exposure to this kind of skill development.

Potential bias: The sample excludes private high schools. This increases the likelihood that the sample is representative of the population, because the study is not concerned with private high schools. Their exclusion from the study will not, therefore, bias the results in one direction or another. Randomness: This is a random sample. This raises the likelihood that the sample is representative of the population.

Potential bias: The sample excludes private high schools. This reduces the likelihood that the sample is representative of the population, because there may be a significant difference between the two groups test scores. Their exclusion from the study may bias the results in one direction or another.

Potential bias: The sample includes private high schools. This increases the likelihood that the sample is representative of the population, because there may be a significant difference between the two groups' test scores. Their inclusion from the study reduces bias of the results in one direction or another.

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Read the following passage. Identify the correct sample and population. From 1903 to 2008, whenever the American League won the World Series, cigarette sales rose 20% over the previous year. But when the National League won the World Series, liquor sales rose 25% for the next year. Stock buyers pay heed! Watch who wins the World Series, and then buy or sell accordingly.

Sample: The results of the World Series from 1903 to 2008 and the correlation to cigarette and liquor sales; Population: Future World Series winners

Sample: The results of the World Series from 1903 to 2008 and the correlation to liquor sales; Population: World Series winners

Sample: The results of the World Series from 1903 to 2008 and the correlation to cigarette sales; Population: Future World Series winners

Sample: Future World Series winners; Population: The results of the World Series and the correlation to sales

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Read the following passage. Identify the sample size, and whether or not the sample is representative of the population referred to in the conclusion. From 1903 to 2008, whenever the American League won the World Series, cigarette sales rose 20% over the previous year. But when the National League won the World Series, liquor sales rose 25% for the next year. Stock buyers pay heed! Watch who wins the World Series, and then buy or sell accordingly.

Sample size: The sample includes the results from 105 years. The sample is certainly large enough to be representative of the past winners, since it includes nearly the entire past population. However, since the researchers are projecting into the future, there may be reasons to think that future society may not be the same as that represented in the sample.

Sample size: The sample includes the results from 105 years. The sample is not large enough to be representative of the past winners, since it excludes much of the entire past population. However, since the researchers are projecting into the future, there may be reasons to think that future society may not be the same as that represented in the sample.

Sample size: The sample is not large enough to be representative of the past winners, since it includes nearly the entire past population.

Sample size: The sample includes the results from 15 years. The sample is certainly large enough to be representative of the past winners, since it includes nearly the entire past population. However, since the researchers are projecting into the future, there may be reasons to think that future society may not be the same as that represented in the sample.

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Instructions: Read the following passage. Determine potential bias and whether or not the sample is random. From 1903 to 2008, whenever the American League won the World Series, cigarette sales rose 20% over the previous year. But when the National League won the World Series, liquor sales rose 25% for the next year. Stock buyers pay heed! Watch who wins the World Series, and then buy or sell accordingly.

Potential bias: The sample clearly shows a past trend. However, since we know that cigarette and liquor sales are affected by many social factors, the extended trend may be a simple correlation and not an indication of any real connection (the issue of correlation is explored further in the next chapter). This allows us to question the likelihood that the sample is representative of the population.

Potential bias: The sample is not suggestive of a past trend. Randomness: The sample is not random.

Potential bias: The sample clearly shows a past trend. However, since we know that cigarette and liquor sales are affected by many social factors, the extended trend may be a simple correlation and not an indication of any real connection (the issue of correlation is explored further in the next chapter). This allows us to question the likelihood that the sample is representative of the population. Randomness: The sample is not random.

Potential bias: Since we know that cigarette and liquor sales are affected by many social factors, the extended trend may be a simple correlation and not an indication of any real connection (the issue of correlation is explored further in the next chapter). This allows us to question the likelihood that the sample is representative of the population.

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