Chapter 2 Exercises
Prerequisites
All material presented in chapter 2
Selected answers
1. Name some ways to graph quantitative variables and some ways to graph qualitative variables. (Ch. 2.B & Ch. 2.C)
2. Based on the frequency polygon displayed below, the most common test grade was around what score? Explain. (Ch. 2.C.3)
3. An experiment compared the ability of three groups of participants to remember
brieflypresented chess positions. The data are shown below. The numbers represent the number of pieces correctly remembered from
three chess positions. Create sidebyside box plots using Analysis Lab or another statistical program for these three groups. What can you
say about the differences between these groups from the box plots?
(Ch. 2.C.4)
Nonplayers 
Beginners 
Tournament players 
22.1 
32.5 
40.1 
22.3 
37.1 
45.6 
26.2 
39.1 
51.2 
29.6 
40.5 
56.4 
31.7 
45.5 
58.1 
33.5 
51.3 
71.1 
38.9 
52.6 
74.9 
39.7 
55.7 
75.9 
43.2 
55.9 
80.3 
43.2 
57.7 
85.3 
4. You have to decide between displaying your data with a histogram or with a stem and leaf display. What factor(s) would affect your choice? (Ch. 2.C.1 & Ch. 2.C.2)
5. In a box plot, what percent of the scores are between the lower and upper hinges? (Ch. 2.C.4)
6. A student has decided to display the results of his project on the number of hours people in various countries slept per night. He compared the sleeping patterns of people from the US, Brazil, France, Turkey, China, Egypt, Canada, Norway, and Spain. He was planning on using a line graph to display this data. Is a line graph appropriate? What might be a better choice for a graph? (Ch. 2.B & Ch. 2.C.7)
7.
For the data from the 1977 Stat. and Biom. 200 class for eye color, construct: (Ch. 2.B)
a. pie graph
b. horizontal bar graph
c. vertical bar graph
d. a frequency table with the relative frequency of each eye color
Eye Color 
Number of students 
Brown 
11 
Blue 
10 
Green 
4 
Gray 
1 
(Question submitted by J. Warren, UNH)
8. A graph appears below showing the number of adults and children who prefer each type of soda. There were 130 adults and kids surveyed. Discuss some ways in which the graph below could be improved.(Ch. 2.B)
9. Which of the box plots on the has a large positive skew? Which has a large
negative skew? (Ch. 2.C.4 & Ch. 1.I)
Questions from Case Studies:
The following questions are from the
Angry Moods (AM) case study.
10. (AM#6) Is there a difference in how much males and females use aggressive behavior to
improve an angry mood? For the "AngerOut" scores:
a. Create parallel box plots. (Ch. 2.C.4)
b. Create a back to back stem and leaf displays (You may have trouble finding a computer to do this so you may have to do it by hand.) (Ch. 2.C.1)
11. (AM#9) Create parallel box plots for the AngerIn scores by sports participation. (Ch. 2.C.4)
12. (AM#11) Plot a histogram of the distribution of the ControlOut scores. (Ch. 2.C.2)
13. (AM#14) Create a bar graph comparing the mean ControlIn score for the athletes and the nonathletes. What would be a better way to display this data? (Ch. 2.C.6)
14. (AM#18) Plot parallel box plots of the Anger Expression Index by sports participation. Does it look like there are any outliers? Which group reported expressing more anger? (Ch. 2.C.4)
The following questions are from the Flatulence (F) case study.
15. (F#1) Plot a histogram of the variable "perday." (Ch. 2.C.2)
16. (F#7) Create parallel box plots of "howlong" as a function gender. What can you say about the results? (Ch. 2.C.4)
17. (F#9) Create a stem and leaf plot of the variable "howlong." What can you say about the shape of the distribution? (Ch. 2.C.1)
The following questions are from the Physicians' Reactions (PR) case study.
18. (PR#1) Create box plots comparing the time expected to be spent with the averageweight
and overweight patients. (Ch. 2.C.4)
19. (PR#4) Plot histograms of the time spent with the averageweight and overweight patients. (Ch. 2.C.2)
20. (PR#5) To which group does the patient with the highest expected time belong?
The following questions are from the Smiles and Leniency (SL) case study.
21. (SL#1) Create parallel boxplots for the four conditions. (Ch. 2.C.4)
22. (SL#3) Create back to back stem and leaf displays for the false smile and neutral
conditions. (It may be hard to find a computer program to do this for you, so be
prepared to do it by hand). (Ch. 2.C.1)
The following questions are from the ADHD Treatment (AT) case study.
23. (AT#3) Create a line graph of the data. Do certain dosages appear to be more effective than others? (Ch. 2.C.7)
24. (AT#5) Create a stem and leaf plot of the number of correct responses of the participants after taking the placebo (d0 variable). What can you say about the shape of the distribution? (Ch. 2.C.1)
Answers:
2) 85
