# Economics exam quiz | Economics homework help

1. The stemplot below displays midterm exam scores for the 34 students taking a Calculus course. The highest possible test score was 100. The teacher declared that an exam grade of 65 or higher was good enough for a grade of “C” or better.

Reference: Ref 1-5

This stemplot is most similar to

A. reporting the five-point summary for the data, with the mean.

B. a histogram with class intervals 30 score < 40, 40 score < 50, etc.

C. a time plot of the data with the observations taken in increasing order.

D. a boxplot of the data.

2 The exam scores (out of 100 points) for all students taking an introductory Statistics course are used to construct the following boxplot.

Reference: Ref 2-3

About 25% of the students scores exceeded

A. 75.

B. 85.

C. 60.

D. 50.

3. A locomotive’s “adhesion” is the locomotive’s pulling force as a multiple of its weight. This is an important performance measure of a locomotive. A diesel locomotive model has adhesion which varies in actual use according to a Normal distribution with mean 0.37 and standard deviation 0.04.

The first quartile of the distribution of adhesion used is

A. 0.29.

B. 0.34.

C. 0.25.

D. 0.04.

4. The histogram below shows the average property damage in millions of dollars caused by tornadoes over a 50-year period in each of the states and Puerto Rico.

Reference: Ref 2-6

From the histogram, which of the following is true?

A. The mean is larger than the median.

B. It is impossible to compare the mean and median for these data.

C. The mean is smaller than the median.

D. The mean and median are approximately equal.

5. The histogram below shows the time visitors to a museum spent browsing an exhibit on a Saturday. There were 300 visitors that day. The following histogram is of the data collected.

Reference: Ref 1-3

The percent of visitors spending more than 85 minutes at the museum is closest to

A. about 5%.

B. about 30%.

C. over 40%.

D. about 20%.

6 Scores on the SAT verbal test in recent years follow approximately the N(515, 109) distribution.

How low must a student score to place in the bottom 5% of all students taking the SAT?

A. 301

B. 729

C. 336

D. 694

7. A company has three divisions and three conference rooms for meetings. To keep track of the use of their facilities, for each meeting held in the company, the division holding the meeting is recorded, the room for the meeting is recorded, and the length of time of the meeting is recorded. Which of the variables is quantitative?

A. the division holding the meeting

B. the conference room for the meeting

C. the length of time for the meeting

D. All of the above

8. A violin student records the number of hours she spends practicing during each of nine consecutive weeks.

6.2

5.0

4.3

7.4

5.8

7.2

8.4

1.2

6.3

Reference: Ref 2-1

Considering the smallest data value (1.2) and using the 1.5 × IQR rule, we would

A. classify the value 1.2 as an outlier because it is more than 1.5 × IQR’s below the median.

B. classify the value 1.2 as an outlier, because it is more than 1.5 × IQR’s below the first quartile.

C. not classify the value 1.2 as an outlier because it is not more than 1.5 × IQR’s below the first quartile.

D. classify the value 1.2 as an outlier because it is more than 1.5 × IQR’s below the mean.

9. A sample was taken of the salaries of 20 employees of a large company. The following is a boxplot of the salaries (in thousands of dollars) for this year.

Reference: Ref 2-5

Based on this boxplot, the five-number summary (in thousands of dollars) is

A. 28, 39, 48, 60.5, 77.

B. 28, 41, 51, 60.5, 77.

C. 28, 39, 51, 58, 77.

D. 28, 41, 48, 58, 77.

10. Does exposure to classical music (through instrument lessons or concert attendance) improve children’s scholastic performance? In a study, researchers measured the amount of exposure to classical music for many children, along with their scores on the state’s academic proficiency exam or not. The explanatory variable in this study is

A. the amount of a child’s exposure to classical music.

B. whether a child passed the state’s proficiency exam.

C. the type of instrument a child plays.

D. the child’s score on the state’s proficiency exam.

11. Scores on the SAT verbal test in recent years follow approximately the N(515, 109) distribution.

Reference: Ref 3-8

The proportion of students scoring between 460 and 550 is closest to

A. 0.681.

B. 0.626.

C. 0.309.

D. 0.317.

12. Using the standard Normal distribution tables, the area under the standard Normal curve corresponding to –0.5 < Z < 1.2 is

A. 0.5764.

B. 0.2815.

C. 0.8849.

D. 0.3085.

13. The stemplot below displays midterm exam scores for the 34 students taking a Calculus course. The highest possible test score was 100. The teacher declared that an exam grade of 65 or higher was good enough for a grade of “C” or better.

Reference: Ref 1-5

The percent of students earning a grade of “C” or higher (as declared by the teacher) is closest to

A. 35%.

B. 80%.

C. 65%.

D. 50%.

14. The exam scores (out of 100 points) for all students taking an introductory Statistics course are used to construct the following boxplot.

Reference: Ref 2-3

Based on this boxplot, the interquartile range is closest to

A. 80.

B. 25.

C. 10.

D. 50.

15. Below is a scatterplot of number of home runs versus number of stolen bases for major league teams in 2009. American League teams are represented by filled circles and National League teams by open circles.

We conclude that

A. all American League teams hit more home runs and stole more bases than did National League teams.

B. there is a weak association for both leagues.

C. there is a strong negative association for American League teams but a positive association for National League teams.

D. there is a strong positive association for American League teams but a negative association for National League teams.

16. Which of the following statements is correct?

A. A negative value for the correlation r indicates the data are strongly unassociated.

B. The correlation always has the same units as the x variable, but not the y variable.

C. Changing the units of measurements of x or y does not change the value of the correlation r.

D. The correlation always has the same units as the y variable, but not the x variable.

17. The following histogram represents the distribution of acceptance rates (percent accepted) among 25 business schools in 2004. In each class interval, the left endpoint is included but not the right, so the class intervals are 10 ≤ rate < 15, 15 ≤ rate < 20, etc.

Reference: Ref 1-4

What percent of the schools have an acceptance rate below 15%?

A. 1%

B. 12%

C. 16%

D. 4%

18. Which of the following sets of four numbers has the greatest standard deviation? Don’t compute!

A. 0, 1, 2, 3

B. 5, 5, 5, 5

C. 7, 8, 9, 10

D. 0, 0, 10, 10

19. Scores on a university exam are Normally distributed with a mean of 78 and a standard deviation of 8. The professor teaching the class declares that a score of 70 or higher is required for a grade of at least “C.”

Reference: Ref 3-2

Using the 68-95-99.7 rule, what percentage of students score below 62?

A. 16%

B. 2.5%

C. 5%

D. 32%

20. Using the standard Normal distribution tables, the area under the standard Normal curve corresponding to Z > –1.62 is

A. 0.0044.

B. 0.9956.

C. 0.9474.

D. 0.0526.

21. For the following density curve, the median is

A. 2.00.

B. 0.50.

C. 1.50.

D. 3.50.

22. A stemplot of ages of 18 faculty members in a college math department follows. 4|3 represents 43 years.

Reference: Ref 2-2

The median age (in years) of the faculty members at Wilmington State is

A. 39.

B. 49.

C. 47.5.

D. 45.

23. Scores on the SAT verbal test in recent years follow approximately the N(515, 109) distribution.

Reference: Ref 3-8

The proportion of students scoring at least 600 is closest to

A. 0.218.

B. 0.782.

C. 0.184.

D. 0.082.

24. A violin student records the number of hours she spends practicing during each of nine consecutive weeks.

6.2

5.0

4.3

7.4

5.8

7.2

8.4

1.2

6.3

Reference: Ref 2-1

What is the interquartile range (IQR) for this data?

A. 2.65 hours

B. 3.20 hours

C. 1.65 hours

D. 3.00 hours

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