Ch. 1-4 MCQ Review

A reporter wishes to portray baseball players as overpaid. Which measure of center should he report as the average salary of major league players?

1. neither the mean nor the median; both will be much lower than the actual average salary.

2. either the mean or median; they will be equal in this case.

3. the median.

4. the mean.

4. the mean

Suppose each employee in the company receives a $3000 raise for next year (each employee's salary is increased by $3000). The interquartile range of the salaries for the employees will

1. be unchanged.

2. be multiplied by 3,000.

3. increase by 3,000.

4. increase by sqrt 3,000.

1. be unchanged

The temperature at any random location in a kiln used in the manufacture of bricks is normally distributed with a mean of 1000 and a standard deviation of 50° F. If bricks are fired at a temperature above 1125°F, they will crack and must be discarded. If the bricks are placed randomly throughout the kiln, the proportion of bricks that crack during the firing process is closest to

1. 47.72%

2. 2.28%

3. 0.62%

4. 49.38%

3. 0.62%

The temperature at any random location in a kiln used in the manufacture of bricks is normally distributed with a mean of 1000 and a standard deviation of 50° F. 

When glazed bricks are put in the oven, if the temperature is below 900°F they will miscolor. If the bricks are placed randomly throughout the kiln, the proportion of glazed bricks that miscolor is closest to

1. 49.38%

2. 2.28%

3. 47.72%

4. 0.62%

2. 2.28%

The scores on a university examination are normally distributed with a mean of 62 and a standard deviation of 3

If the bottom 5% of students will fail the course, what is the lowest mark that a student can have and still be awarded a passing grade?

1. 62

2. 57

3. 44

4. 40

2. 57

The study described in the previous question found that children who watch more television tend to have lower reading scores than children who watch fewer hours of television. The study report says that, “Hours of television watched explained 9% of the observed variation in the reading scores of the 125 subjects.” The correlation between hours of TV and reading score must be

1. r = - 0.3

2. Can’t tell from information given.

3. r = 0.09

4. r = 0.3

5. r = -0.09

1. r = -0.3

Biologists have collected data relating the age (in years) of one variety of oak tree to its height (in feet). A scatterplot for 20 of these trees is given at right.   If the point labeled A in the above scatterplot were changed to have a height of 40 feet, which one of the following statements would be true?

1. The slope of the least squares regression line would decrease and the correlation would increase.

2. The slope of the least squares regression line would decrease and the correlation would decrease. 

3. The slope of the least squares regression line would increase and the correlation would increase. 

4. The slope of the least squares regression line and the correlation would remain the same. 

3. The slope of the least squares regression line would increase and the correlation would increase. 

A least squares regression line was fitted to the weights (in pounds) versus age (in months) of a group of many young children. The equation of the line is  ŷ = 16.6 + 0.65t, where ŷ is the predicted weight and t is the age of the child. A 20-month-old child in this group has an actual weight of 25 pounds. Which of the following is the residual weight, in pounds, for this child? 

1. - 7.85

2. - 4.60

3. 4.60

4. 5.00

5. 7.85

2. - 4.60

Looking for a link between smoking and cancer, researchers surveyed a large sample of adults. For each adult they recorded whether the person had smoked regularly at any period in his or her life and whether the person had cancer. They then compared the proportion of cancer cases in those who had smoked regularly at some time with the proportion of cases in those who had never smoked regularly at any point. The researchers found there was a higher proportion of cancer cases among those who had smoked regularly than among those who had never smoked regularly. This is

1. a matched pairs study, causation can not be determined

2. an experiment, not matched pairs

3. a double-blind experiment

4. a randomized block experiment, causation can be determined.

5. an observational study, causation can not be determined.

5. an observational study, causation can not be determined.

A news release for a diet products company reports: “There's good news for the 65 million Americans currently on a diet.” Its study showed that people who lose weight can keep it off. The sample was 20 graduates of the company's program who endorse it in commercials. The results of the sample are probably

1. biased, overstating the effectiveness of the diet.

2. unbiased since these are nationally recognized individuals.

3. biased, understating the effectiveness of the diet.

4. biased, but they could be more accurate. A larger sample size should be used.

5. biased, overstating the effectiveness of the diet.

6. unbiased because all 20 people lost weight.

5. biased, overstating the effectiveness of the diet.

Twelve people who suffer from chronic fatigue syndrome volunteer to take part in an experiment to see if shark fin extract will increase one's energy level. Eight of the volunteers are men and four are women. Half of the volunteers are to be given shark fin extract twice a day and the other half a placebo twice a day. We wish to make sure that four men and two women are assigned to each of the treatments, so we decide to use a block design with the men forming one block and the women the other. Referring to the information, a block design is appropriate in this experiment if

1. we believe men and women will respond differently to treatments

2. gender equity is an important legal consideration in this study.

3. we couldn't find an equal number of men and women who suffer from low energy level.

4. we want the conclusions to apply equally to men and women.

5. all statements are correct.

1. we believe men and women will respond differently to treatments

New varieties of corn with altered amino acid patterns may have higher nutritive value than standard corn, which is low in the amino acid lysine. An experiment compares two new varieties, called opaque-2 and floury-2, with normal corn. Corn-soybean meal diets using each type of corn are prepared at three different protein levels, 12%, 16%, and 20%, giving nine diets in all. Researchers assign 10 one-day-old male chicks to each diet and record their weight gains after 21 days. The weight gain of the chicks is a measure of the nutritive value of their diet.  The experimental units in this experiment are

1. variety and protein level.

2. the weight gain.

3. the 90 one-day-old male chicks.

4. the three different protein levels; 12%, 16%, and 20%.   

5. opaque-2 and floury-2.

3. the 90 one-day-old male chicks.

New varieties of corn with altered amino acid patterns may have higher nutritive value than standard corn, which is low in the amino acid lysine. An experiment compares two new varieties, called opaque-2 and floury-2, with normal corn. Corn-soybean meal diets using each type of corn are prepared at three different protein levels, 12%, 16%, and 20%, giving nine diets in all. Researchers assign 10 one-day-old male chicks to each diet and record their weight gains after 21 days. The weight gain of the chicks is a measure of the nutritive value of their diet. The response variable is

1. variety and protein level.

2. the weight gain.

3. the 90 one-day-old male chicks.

4. the three different protein levels; 12%, 16%, and 20%.   

5. opaque-2 and floury-2.

2. the weight gain

In a study of personal grooming habits of Americans, one of the questions asked is this: “How often do you brush your teeth?” The responses to this question should not be trusted because of:

1. voluntary response bias

2. response bias

3. non-response bias

4. sampling error

2. response bias