STA2023 Chapter 2 - The first two classes of a frequency

STA2023

Chapter 2

INSTRUCTIONS:  Answer all questions. Shade the correct answer in your scantron for each of the questions on the quiz. 

1. The first two classes of a frequency distribution are 0-19 and 20-39. What is the class width?

(a) 19 (b) 10 (c) 19.5 (d) 9.5 (e) 20

2. The first two classes of a frequency distribution are 0-19 and 20-39. What is the class mid-point for the second class?

(a) 20.5 (b) 19.5  (c) 14.5 (d) 29.5 (e) 39.5

3. What characteristic of a data set can be better understood by constructing a histogram?

(a) Shape (b) Variation (c) Center (d) Outliers (e) position

The test scores of 45 students are summarized in the frequency table below

  

Score

 

Students

 

20-29

 

5

 

30-39

 

10

 

40-49

 

15

 

50-59

 

10

 

60-69

 

5

4. What is the lower limit for the second class?

(a) 39.5 (b) 29.5 (c) 34.5 (d) 39 (e) 30

5. What is the class width in the frequency table above?

(a) 9 (b) 10 (c) 24.5 (d) 34.5 (e) 20

6. What is the class mid-point for the class 40 –49

(a) 34.5 b) 44.5  (c) 39.5 (d) 49.5 (e) 40

7. What are the upper limits for the last class?

(a) 60 (b) 69 (c) 59.5 (d) 69.5 (e) 64.5

8. What are the upper and lower boundaries for the third class?

(a) 39.5 – 49.5 (b) 40.5 – 49.5 (c) 40 – 49 (d) 34.5 - 44.5

9. What is the relative frequency corresponding to the frequency of 15 for the third class?

(a) 15% (b) 35% (c) 66.6% (d) 33.3% (e) 37.5%

10. What is the modal class?

(a) 20-29 (b) 30-39 (c) 40-49 (d) 50-59 (e) 60-69

11. What values are represented in the stemplot below?

  

stem

 

leaves

 

4

 

0

 

7

 

5

 

4

 

4

 

6

 

8

 

9

(a) 40, 47, 54, 59, 68, 60  (b) 41, 47, 54, 59, 68, 69

(c) 40, 47, 68, 61, 71, 76 (d) 40, 47, 54, 54, 68, 69

12. All of the following are characteristics of data EXCEPT:

(a) Center (b) Variation (c) Distribution (d) Position

13. Each of the following is a characteristic of a normal distribution EXCEPT:

(a) It is approximately symmetric

(b) It is approximately bell-shaped

(c) The number of data values preceding the maximum value is approximately the same as the number of values following the maximum value

(d) The frequencies start at zero, increases to a maximum and then decreases to zero

(e) The frequencies start low, then increase to one or two high frequencies, then decrease to a low frequency

14. A _________ is a graph consisting of bars of equal width drawn adjacent to each other. The horizontal scale represents classes of quantitative data values and the vertical scale represents frequencies. The heights of the bars correspond to the frequency values.

(a) Bar-Graph (b) Histogram (c) Frequency Polygon (d) Stemplot

15. True or False. When a die is rolled 600 times, each of the 6 possible outcomes occurs about 100 times as we normally expect, so the frequency distribution summarizing the results is an example of a normal distribution.

(a) True (b) False

16. Which graph is best for paired data consisting of the shoe size and heights of 30 randomly selected students?

(a) Histogram (b) dotplot (c) scatterplot (d) Pie Chart

17. Statistical graphs are used for each of the following EXCEPT

(a) To discover a trend or pattern over time

(b) To summarize a data set

(c) To facilitate computational procedures for solving probabilities

(d) To capture an audience attention

(e) To reinforce a critical point

18. True or false. In the construction of a frequency polygon, the class limits are used for the x axis.

(a) True (b) False

19. Data such as blood types (A, B, AB, O) can be organized by using a:

(a) Grouped frequency distribution (b) Stem and leaf plot

(c) Categorical frequency distribution (d) dotplot

20. True or False: If there are no data values for a particular class in a frequency distribution, that particular class can be eliminated. 

(a) True (b) False

21. The first two classes of a frequency distribution are 0-9 and 10-19. What are the class boundaries for the second class?

(a) 9.5 & 10.5 (b) 9.5 & 19.5

(c) 10.5 & 19.5 (d) 10 & 19

22. What type of graph displays the data by using lines that connect points plotted for the frequencies at the midpoints of the classes?

(a) Histogram (b) Frequency Polygon (c) Cumulative frequency graph (d) Time series graph

23. What type of graph is used to visually represent the number of values that are below a certain upper class boundary?

(a) Histogram (b) Frequency Polygon (c) Cumulative frequency graph (d) Time series graph (e) Dot plot

24. All of the following are important characteristics of data EXCEPT

(a) Variation (b) Center (c) Distribution (d) Outliers (e) position

25. True or False. Quantitative variables can be summarized using frequency and relative frequency distributions.

(a) True (b) False

26. True or False. Stem and leaf displays contain more information than either a frequency distribution or histogram.

(a) True (b) False

27. What type of graph will best illustrate the changes in mean global temperatures from 1902 to 2015?

(a) Histogram (b) Bar graph (c) Time series graph (d) stem and leaf plot

Figure 1 below shows the emergency injuries suffered by 20,000 teenagers in the United States in 2014. 

 

Figure 1

28. What is the most common injury?

(a) Fractures (b) Cuts and bruises (c) Other injury (d) Strains and sprains

29. Of the specific injuries shown, what is the least common injury?

(a) Strains & sprains (b) Cuts and bruises (c) Traumatic brain injury  (d) Fractures

30. What is the percentage for cuts and bruises?

(a)  10% (b) 20% (c) 25% (d) 15% (e) 26%

31. What is the percentage for fractures?

(a)  25% (b) 20% (c) 15% (d) 26% (e) 24%

32. Approximately how many teenagers suffered traumatic brain injury in 2014?

(a) 1,800 (b) 2,000 (c) 200 (d) 180 (e) 2,400

Answer questions 33, 34, 35, and 36 on separate sheets of paper and turn in with your scantron. 

33. The ages of the Vice Presidents of the United States at the time of their death are listed below. Construct a frequency distribution to summarize the data. Use 6 classes. List the relative and cumulative frequencies. List the class boundaries and class midpoints. Use Excel to construct a histogram to display the data.

90 83 80 73 70 51 68 79 70 71 72 74 67 54 81 66 62 63 68 57 66 96 78 55 60 66 57 71 60 85 76 98 77 88 78 81 64 66 77 70

34. Refer to the data set in question 33 above. Construct a stem and leaf plot to depict the ages of the vice-presidents at the time of their deaths.

35. Use EXCEL to construct a Pareto chart for the number of tons (in millions) of trash recycled per year by Americans based on an Environmental Protection Agency study. 

  

Type

 

Amount

 

Paper

 

320

 

Iron/steel

 

282

 

Aluminum

 

268

 

Yard waste

 

242

 

Glass

 

196

 

Plastics

 

42

Source: USA TODAY

36. The table below shows the percentage of high school students who said they had used marijuana one or more times from 1991 to 2010. Construct a time-series chart to display the data.

  

Year

 

Percent of HS students using   marijuana one or more times

 

1997

 

31

 

1998

 

32

 

1999

 

34

 

2000

 

35

 

2001

 

37

 

2002

 

41

 

2003

 

44

 

2004

 

48

 

2005

 

52

 

2006

 

50

 

2007

 

48

 

2008

 

47

 

2009

 

46

 

2010

 

45