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Section 2-2 #’s 3, 7, 9, 11
- Find the class boundaries, midpoints, and widths for each class.
a) 12 – 18 b) 56 – 74 c) 695 – 705 d) 13.6 – 14.7 e) 2.15 – 3.
Class Limits Class Boundaries Midpoints Class Width
- Trust in Internet Information A survey was taken on how much trust people place in the information they read on the Internet. Construct a categorical frequency distribution for the data. A = trust in everything they read, M = trust in most of what they read, H = trust in about one-half of what they read, S = trust in a small portion of what they read.
M M M A H M S M H M
S M M M M A M M A M
M M H M M M H M H M
A M M M H M M M M M
Class Limit Frequency f Percent %
A 4
M 28
H 6
S 2
Total 40
- Charging Elephant Speeds The following data are the measured speeds in miles per hour of 30 charging elephants. Construct a grouped frequency distribution for the data. From the distribution, estimate an approximate average speed of a charging elephant. Use 5 classes.
25 24 25 24 25
23 25 19 32 23
22 24 26 25 23
28 25 25 26 27
22 28 24 23 24
21 25 22 29 23
Range = 32-19 = 13 ; # of classes = 5 ; class width = Roundup (
) = Roundup (2.6) = 3
Class Limits
Boundaries Frequency f Mid-point R f % C f
Total 30
- GRE Scores at Top-Ranked Engineering Schools The average quantitative GRE scores for the top 30 graduate schools of engineering are listed. Construct a frequency distribution with 6 classes.
767 770 761 760 771 768 776 771 756 770
763 760 747 766 754 771 771 778 766 762
780 750 746 764 769 759 757 753 758 746
H = 780 ; L = 746 ; Range = 780 – 746 = 34 ; # of classes = 6 ; class width = Roundup (
Roundup ( 5.6 ) = 6
b) Frequency Polygon:
c) Ogive:
- Automobile Fuel Efficiency Thirty automobiles were tested for fuel efficiency, in miles per gallon (mpg). The following frequency distribution was obtained. Construct a histogram, frequency polygon, and ogive for the data.
Class boundaries Frequency C f Midpoint 7.5 – 12.5 3 3 10
12.5 – 17.5 5 8 15 17.5 – 22.5 15 23 20 22.5 – 27.5 5 28 25 27.5 – 32.5 2 30 30
a) Histogram:
b) Frequency Polygon:
c) Ogive:
- Cereal Calories The number of calories per serving for selected ready-to-eat cereals is listed here. Construct a frequency distribution using 7 classes. Draw a histogram, frequency polygon, and ogive for the data, using relative frequencies. Describe the shape of the histogram.
c) Ogive:
- Protein Grams in Fast Food The amount of protein (in grams) for a variety of fast-food sandwiches is reported here. Construct a frequency distribution using 6 classes. Draw a histogram, frequency polygon, and ogive for the data, using relative frequencies. Describe the shape of the histogram.
23 30 20 27 44 26 35 20 29 29
25 15 18 27 19 22 12 26 34 15
27 35 26 43 35 14 24 12 23 31
40 35 38 57 22 42 24 21 27 33
L = 12 ; H = 57 ; Range = 57 – 12 = 45 ; # of classes = 6 ; Class width = Roundup (
) = Roundup ( 7.5) = 8
Class Limits Frequency Boundaries Mid-point C f R f %
Total 40
a) Histogram:
b) Frequency Polygon:
The best place to market products would be to the home viewers.
- World Energy Use The following percentages indicate the source of energy used worldwide.
Construct a Pareto chart for the energy used.
Petroleum 39.8% Coal 23.2% Dry natural gas 22.4% Hydroelectric 7.0% Nuclear 6.4% Other (wind, solar, etc.)
- Airline Departures draw a time series graph to represent the data for the number of airline departures (in millions) for the given years. Over the years, is the number of departures increasing, decreasing, or about the same?
Year 1996 1997 1998 1999 2000 2001 2002
Number of departures
There was an increase in the number of departures until 2000, then a decrease in 2001, and then an increase.
- Tobacco Consumption the data represent the personal consumption (in billions of dollars) for
tobacco in the United States. Draw a time series graph for the data and explain the trend.
Year 1995 1996 1997 1998 1999 2000 2001 2002 Amount 8.5 8.7 9.0 9.3 9.6 9.9 10.2 10.
There is a steady increase in consumption of tobacco products.
- Reasons We Travel The following data are based on a survey from American Travel Survey on
why people travel. Construct a pie graph for the data and analyze the results.
Purpose Number Percent Personal business (PB)
Double Stem and Leaf Plot
The distribution is almost bell-shaped curve.
- Car Thefts in Large Cities The National Insurance Crime Bureau reported that these data represent the number of registered vehicles per car stolen for 35 selected cities in the United States. For example, in Miami, 1 automobile is stolen for every 38 registered vehicles in the city. Construct a stem and leaf plot for the data and analyze the distribution. (The data have been rounded to the nearest whole number.)
38 53 53 56 69 89 94
41 58 68 66 69 89 52
50 70 83 81 80 90 74
50 70 83 59 75 78 73
92 84 87 84 85 84 89
Stem Leaf 4 23 4 667899 5 011112244444 5 555566677778 6 0111244 6 589
The distribution has two peaks, and the data are grouped somewhat toward the numerically higher end of the distribution.
Section 2-5 #’s 6, 7, 13
- Hours Spent Jogging A researcher wishes to determine whether the number of hours a person jogs per week is related to the person’s age. Draw a scatter plot and comment on the nature of the relationship.
Age, x 34 22 48 56 62 Hours, y 5.5 7 3.5 3 1
- Recreational Expenditures A study was conducted to determine if the amount a person spends
per month on recreation is related to the person’s income. Draw a scatter plot and comment on the nature of the relationship.
Income, x $800 $1200 $1000 $900 $850 $907 $
