SAT Math Scores The following relative frequency ogive

Problem 3E True or False: When plotting an ogive, the plotted points have x-coordinates that are equal to the upper limits of each class.

Problem 1E What is an ogive?

Problem 2E What are time-series data?

Problem 4E True or False: When plotting a frequency polygon, we plot the percentages for each class above the midpoint and connect the points with line segments.

Age of Population The following frequency polygon shows the age distribution of U.S. residents below 100 years of age on July 1, 2009. (a) What is the class width? How many classes are represented in the graph? (b) What is the midpoint of the first class? What are the lower and upper limits of the first class? (c) What is the midpoint of the last class? What are the lower and upper limits of the last class? (d) Which age group has the highest population? Estimate the population of this age group. (e) Which age group has the lowest population? Estimate the population of this age group. (f ) Approximate the total number of U.S. residents below 100 years of age on July 1, 2009. (g) Between which two classes is the change in population most extreme? Least extreme?

ACT Scores The relative frequency ogive on the following page represents the ACT composite score for the high school graduating class of 2010. (a) Estimate the percentage of students who had a composite score of 16 or below. (b) Estimate the percentage of students who had a composite score of 19 or above. (c) If 1,568,835 students from the class of 2010 took the ACT exam, approximately how many students had a score of 16 or below? 25 or above? (d) What is the approximate score at which half the students scored better, and half scored worse?

Deaths by Legal Intervention Deaths by legal intervention refers to injuries inflicted by law-enforcement agents in the course of arresting or attempting to arrest lawbreakers, suppressing disturbances, maintaining order, and other legal action (including legal execution). In 2006, 174 such deaths occurred in 16 states in the United States. The following frequency polygon represents these deaths by age. (a) What is the class width? How many classes are represented in the graph? (b) What is the midpoint of the first class? What are the lower and upper limits of the first class? (c) What is the midpoint of the last class? What are the lower and upper limits of the last class? (d) Which age group had 35 deaths due to legal intervention? (e) Which two age groups have the highest number of deaths due to legal intervention? Estimate the number of deaths for these age groups. (f ) Estimate the relative frequency for the class 20–29.

SAT Math Scores The following relative frequency ogive represents the SAT math scores of college-bound students. (a) What is the class width? How many classes are represented in the graph? (b) What are the lower and upper limits of the first class? (c) What are the lower and upper limits of the last class? (d) Estimate the percentage of students who had a math score of 450 or below. (e) Estimate the percentage of students who had a math score above 500. (f ) In which class did the most students fall?

Motor Vehicle Production The following time-series graph shows the annual U.S. motor vehicle production from 1990 through 2008. (a) Estimate the number of motor vehicles produced in the United States in 1991. (b) Estimate the number of motor vehicles produced in the United States in 1999. (c) Use your results from (a) and (b) to estimate the percent increase in the number of motor vehicles produced from 1991 to 1999. (d) Estimate the percent decrease in the number of vehicles produced from 1999 to 2008.

Housing Affordability The National Association of Home Builders in conjunction with Wells Fargo compiles a housing affordability index called the Housing Opportunity Index (HOI). The index represents the proportion of homes considered to be affordable according to standard mortgage practices for individuals earning the national median income. (a) Estimate the HOI in the first quarter of 1999 (Q1/99). (b) What was the lowest value of the HOI (meaning homes were least affordable)? In what year did this occur? (c) What was the highest value of the HOI? In what year did this occur? (d) Determine the percentage decrease in the HOI from the first quarter of 1999 to the third quarter of 2006. (e) Determine the percentage increase in the HOI from its low to its high.

Unemployment and Inflation The following time-series plot shows the annual unemployment and inflation rates for the years 1988 through 2009. (a) Estimate the unemployment and inflation rates for 1992. (b) Estimate the unemployment and inflation rates for 2009. (c) The misery index is defined as the sum of the unemployment rate and the inflation rate. Use your results from (a) and (b) to estimate the misery index for the years 1992 and 2009. (d) Describe any relationship that might exist between the unemployment rate and inflation rate over the time period shown.

Problem 13E In Problems, use the frequency distributions in the problem indicated from Section to do the following: Tuition The following data represent the tuition for all 2-year public community colleges in California in 2009-2010. Tuition (dollars) Number of Community Colleges 775-799 22 800-824 68 825-849 15 850-874 5 875-899 0 900-924 0 925-949 0 950-974 1 Source: Chronicle of Higher Education (a) Construct a cumulative frequency distribution. ________________ (b) Construct a cumulative relative frequency distribution. ________________ (c) Draw a frequency polygon. ________________ (d) Draw a frequency ogive. ________________ (e) Draw a relative frequency ogive.

Problem 14E In Problems, use the frequency distributions in the problem indicated from Section to do the following: Earthquakes The following data represent the number of earthquakes worldwide in 2010 with magnitudes less than 9.0 (as of October 15, 2010). Magnitude Number 0-0.9 22 1.0-1.9 22 2.0-2.9 3201 3.0-3.9 3332 4.0-4.9 7276 5.0-5.9 1430 6.0-6.9 130 7.0-7.9 18 8.0-8.9 1 Source: U.S. Geological Survey, Earthquake Hazards Program (a) Construct a cumulative frequency distribution. ________________ (b) Construct a cumulative relative frequency distribution. ________________ (c) Draw a frequency polygon. ________________ (d) Draw a frequency ogive. ________________ (e) Draw a relative frequency ogive.

Prize Money at Wimbledon The following time-series plot shows the prize money (in pounds) awarded at the Wimbledon Tennis Championship to the winners of the men’s singles and ladies’ singles competitions from 1995 through 2010. (a) Estimate the prize money awarded to each for men’s and ladies’ singles in 1996. (b) Estimate the prize money awarded to each for men’s and ladies’ singles in 2006. (c) Describe any relationship that might exist between the prize money awarded for men’s and ladies’ singles over the time period shown. (d) Use the graph to determine what happened for the first time in 2007. Estimate the prize money awarded for each championship in 2007. (e) Estimate the percent increase in prize money awarded to each for men’s and ladies’ singles from 2009 to 2010.

Problem 15E In Problems, use the frequency distributions in the problem indicated from Section to do the following: Average Income The following data represent the per capita (average) disposable income (income after taxes) for the 50 states and the District of Columbia in 2009. 30,103 33,096 35,507 37,916 41,344 43,874 30,875 33,725 35,667 38,081 41,411 45,705 31,632 33,786 35,676 38,503 41,552 46,957 31,799 34,004 36,484 38,578 41,751 48,285 31,883 34,025 36,745 39,530 42,009 49,875 31,946 34,089 36,751 39,578 42,325 50,313 32,219 34,453 36,822 39,817 42,603 54,397 32,935 35,268 36,935 41,003 42,831 66,000 32,992 35,381 37,780 Source: U.S. Bureau of Economic Analysis, March 2010 With the first class having a lower class limit of 30,000 and a class width of 6000: (a) Construct a cumulative frequency distribution. ________________ (b) Construct a cumulative relative frequency distribution. ________________ (c) Draw a frequency polygon. ________________ (d) Draw a frequency ogive. ________________ (e) Draw a relative frequency ogive.

Problem 16E In Problems, use the frequency distributions in the problem indicated from Section to do the following: Uninsured Rates The following data represent the percentage of people without health insurance for the 50 states and the District of Columbia in 2009. 4.2 10.6 12.6 14.8 17.8 18.9 21.4 8.6 10.6 13.0 15.5 18.1 19.4 22.2 9.2 10.9 13.3 15.9 18.3 19.6 25.0 9.6 10.9 13.4 15.9 18.3 19.7 9.6 11.3 13.9 16.1 18.4 20.6 9.7 11.4 14.0 16.1 18.4 21.1 10.2 11.6 14.3 16.1 18.6 21.2 10.5 12.3 14.7 16.2 18.7 21.3 Source: Gallup With the first class having a lower class limit of 4 and a class width of 2: (a) Construct a cumulative frequency distribution. ________________ (b) Construct a cumulative relative frequency distribution. ________________ (c) Draw a frequency polygon. ________________ (d) Draw a frequency ogive. ________________ (e) Draw a relative frequency ogive.

Problem 17E Walt Disney CompanyThe data on the next page represent the stock price for the Walt Disney Company at the end of each month in 2010. Construct a time-series plot and comment on any trends. What was the percent change in the stock price of Disney from January 2010 to December 2010? Date Closing Price Date Closing Price 1/10 28.71 7/10 30.72 2/10 28.99 8/10 31.55 3/10 31.34 9/10 32.68 4/10 35.01 10/10 36.13 5/10 31.00 11/10 36.51 6/10 31.36 12/10 37.51 Source: TD Ameritrade

Problem 18E Google, Inc. The following data represent the closing stock price for Google, Inc. at the end of each year since it first went public in 2004 until the end of 2010. Construct a time-series plot and comment on any trends. What was the percent change in Google stock from 2009 to 2010? Date Closing Price Date Closing Price 2004 192.79 2008 307.65 2005 414.86 2009 619.98 2006 460.48 2010 593.97 2007 691.48 Source: TD Ameritrade

Problem 19E Federal Debt The following data represent the percentage of total federal debt as a percentage of gross domestic product (GDP). The GDP of a country is the total value of all goods and services produced within the country in a given year. Construct a time-series plot and comment on any trends. Year Debt as % of GDP Year Debt as % of GDP 1991 61.17 2001 56.46 1992 64.09 2002 58.52 1993 66.17 2003 60.88 1994 66.23 2004 62.18 1995 67.08 2005 62.77 1996 66.66 2006 63.49 1997 64.97 2007 63.99 1998 62.84 2008 69.15 1999 60.47 2009 83.29 2000 57.02 2010 94.27 Source: http://www.usgovernmentspending.com/federal_debt_chart.html

Problem 20E College Enrollment The data in the next column represent the percentage of 18- to 24-year-olds enrolled in college. Construct a time-series plot and comment on any trends. Year Percent Enrolled Year Percent Enrolled 1991 33.3 2000 35.5 1992 34.4 2001 36.3 1993 34.0 2002 36.7 1994 34.6 2003 37.8 1995 34.3 2004 38.0 1996 35.5 2005 38.9 1997 36.8 2006 37.3 1998 36.5 2007 38.8 1999 35.6 2008 39.6 Source: U.S. Center for Education Statistics

Problem 21E Rates of Return of Stocks Stocks may be categorized by industry. The following data represent the 5-year rates of return for a sample of consumer goods stocks and energy stocks ending October 20, 2010. Consumer Goods 5.51 11.42 18.09 10.26 5.82 26.38 8.33 2.57 12.07 ?0.37 4.73 24.6 ?1.54 9.31 7.40 10.69 14.84 0.66 6.64 ?14.74 10.84 15.18 8.08 11.34 21.43 1.53 7.00 1.63 ?7.48 3.45 14.73 8.62 ?0.60 ?1.72 36.36 Energy 3.50 2.68 4.43 3.59 20.77 16.04 15.88 9.09 3.69 14.99 15.82 3.99 14.34 17.16 ?4.51 29.97 5.95 ?1.29 ?9.04 11.77 11.68 6.82 12.22 10.69 16.67 8.92 2.76 14.76 2.39 ?3.29 5.71 ?2.55 6.06 7.39 3.90 Source: Morningstar (a) Construct a frequency distribution for each industry. To make an easy comparison, create each frequency distribution so that the lower class limit of the first class is ? 20 and the class width is 10. ________________ (b) Construct a relative frequency distribution for each industry. ________________ (c) On the same graph, construct a relative frequency polygon for the two industries. ________________ (d) On the same graph, construct a relative frequency ogive for the two industries. ________________ (e) Which industry appears to have the better performance for the 5-year period? Support your opinion.

Problem 26E What type of variable is required when drawing a time-series plot? Why do we draw time-series plots?

American League versus National League The following data represent the earned-run average (ERA) of the top 40 pitchers in both the American League and National League in 2010. Note: ERA is the average number of earned runs given up per 9 innings. Note: Be sure to take into account the fact that the National League does not have a designated hitter. (a) Why would it be appropriate to use frequencies to compare the two leagues? (b) Construct a frequency distribution for each league. To make an easy comparison, create each frequency distribution so that the lower class limit of the first class is 2.0 and the class width is 0.50. (c) On the same graph, construct a frequency polygon for the American and National Leagues. (d) On the same graph, construct a frequency ogive for the American and National Leagues. (e) Which league appears to have better pitchers? Support your opinion.

Problem 24E Which do you prefer: histograms, stem-and-leaf plots, or frequency polygons? Be sure to support your opinion. Are there circumstances in which one might be preferred over another?

Putting It Together: Shark! The following two graphics represent the number of reported shark attacks worldwide since 1900 and the worldwide fatality rate of shark attacks since 1900. Write a report about the trends in the graphs. In your report discuss the apparent contradiction between the increase in shark attacks, but the decrease in fatality rate.

Problem 25E The cumulative relative frequency for the last class must always be 1. Why?

What is an ogive?

What are time-series data?

True or False: When plotting an ogive, the plotted points have x-coordinates that are equal to the upper limits of each class.

True or False: When plotting a frequency polygon, we plot the percentages for each class above the midpoint and connect the points with line segments.

Age of Population The following frequency polygon shows the age distribution of U.S. residents below 100 years of age on July 1, 2009.(a) What is the class width? How many classes are represented in the graph? (b) What is the midpoint of the first class? What are the lower and upper limits of the first class? (c) What is the midpoint of the last class? What are the lower and upper limits of the last class? (d) Which age group has the highest population? Estimate the population of this age group. (e) Which age group has the lowest population? Estimate the population of this age group. (f ) Approximate the total number of U.S. residents below 100 years of age on July 1, 2009. (g) Between which two classes is the change in population most extreme? Least extreme?

Deaths by Legal Intervention Deaths by legal intervention refers to injuries inflicted by law-enforcement agents in the course of arresting or attempting to arrest lawbreakers, suppressing disturbances, maintaining order, and other legal action (including legal execution). In 2006, 174 such deaths occurred in 16 states in the United States. The following frequency polygon represents these deaths by age.(a) What is the class width? How many classes are represented in the graph? (b) What is the midpoint of the first class? What are the lower and upper limits of the first class? (c) What is the midpoint of the last class? What are the lower and upper limits of the last class? (d) Which age group had 35 deaths due to legal intervention? (e) Which two age groups have the highest number of deaths due to legal intervention? Estimate the number of deaths for these age groups. (f ) Estimate the relative frequency for the class 2029.

ACT Scores The relative frequency ogive on the following page represents the ACT composite score for the high school graduating class of 2010. (a) Estimate the percentage of students who had a composite score of 16 or below. (b) Estimate the percentage of students who had a composite score of 19 or above.(c) If 1,568,835 students from the class of 2010 took the ACT exam, approximately how many students had a score of 16 or below? 25 or above? (d) What is the approximate score at which half the students scored better, and half scored worse?

SAT Math Scores The following relative frequency ogive represents the SAT math scores of college-bound students. (a) What is the class width? How many classes are represented in the graph?Class of 2010 SAT Mathematics Score 0 0.2 0.4 0.6 0.8 1.0 0 100 200 300 400 Score 500 600 700 800 900 Source: The College Board, 2010 College-Bound Seniors Total Group Profile Report, 2010 (b) What are the lower and upper limits of the first class? (c) What are the lower and upper limits of the last class? (d) Estimate the percentage of students who had a math score of 450 or below. (e) Estimate the percentage of students who had a math score above 500. (f ) In which class did the most students fall?

Housing Affordability The National Association of Home Builders in conjunction with Wells Fargo compiles a housing affordability index called the Housing Opportunity Index (HOI). The index represents the proportion of homes considered to be affordable according to standard mortgage practices for individuals earning the national median income.Housing Opportunity Index 0 10 20 30 40 50 60 70 80 Q1/99 Q2/99 Q3/99 Q4/99 Q1/00 Q2/00 Q3/00 Q4/00 Q1/01 Q2/01 Q3/01 Q4/01 Q1/02 Q4/03 Q1/04 Q2/04 Q3/04 Q4/04 Q1/05 Q2/05 Q3/05 Q4/05 Q1/06 Q2/06 Q3/06 Q4/06 Q1/07 Q2/07 Q3/07 Q4/07 Q1/08 Q2/08 Q3/08 Q4/08 Q1/09 Q2/09 Q3/09 Q4/09 Q1/10 Q (a) Estimate the HOI in the first quarter of 1999 (Q1/99). (b) What was the lowest value of the HOI (meaning homes were least affordable)? In what year did this occur? (c) What was the highest value of the HOI? In what year did this occur? (d) Determine the percentage decrease in the HOI from the first quarter of 1999 to the third quarter of 2006. (e) Determine the percentage increase in the HOI from its low to its high.

Motor Vehicle Production The following time-series graph shows the annual U.S. motor vehicle production from 1990 through 2008.Annual U.S. Motor Vehicle Production 6000 7000 8000 9000 10,000 11,000 12,000 13,000 14,000 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 Year Source: Bureau of Transportation Statistics (a) Estimate the number of motor vehicles produced in the United States in 1991. (b) Estimate the number of motor vehicles produced in the United States in 1999. (c) Use your results from (a) and (b) to estimate the percent increase in the number of motor vehicles produced from 1991 to 1999. (d) Estimate the percent decrease in the number of vehicles produced from 1999 to 2008.

Unemployment and Inflation The following time-series plot shows the annual unemployment and inflation rates for the years 1988 through 2009.Unemployment & Inflation Rates 0 1 1 2 3 4 5 6 8 9 7 10 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Year (a) Estimate the unemployment and inflation rates for 1992. (b) Estimate the unemployment and inflation rates for 2009. (c) The misery index is defined as the sum of the unemployment rate and the inflation rate. Use your results from (a) and (b) to estimate the misery index for the years 1992 and 2009. (d) Describe any relationship that might exist between the unemployment rate and inflation rate over the time period shown

Prize Money at Wimbledon The following time-series plot shows the prize money (in pounds) awarded at the Wimbledon Tennis Championship to the winners of the mens singles and ladies singles competitions from 1995 through 2010 Wimbledon Prize Money 1,100,000 1,000,000 900,000 800,000 700,000 600,000 500,000 400,000 300,000 200,000 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Mens Single Ladies Single (a) Estimate the prize money awarded to each for mens and ladies singles in 1996. (b) Estimate the prize money awarded to each for mens and ladies singles in 2006. (c) Describe any relationship that might exist between the prize money awarded for mens and ladies singles over the time period shown. (d) Use the graph to determine what happened for the first time in 2007. Estimate the prize money awarded for each championship in 2007. (e) Estimate the percent increase in prize money awarded to each for mens and ladies singles from 2009 to 2010.

In Problems 1316, use the frequency distributions in the problem indicated from Section 2.2 to do the following: (a) Construct a cumulative frequency distribution. (b) Construct a cumulative relative frequency distribution. (c) Draw a frequency polygon. (d) Draw a frequency ogive. (e) Draw a relative frequency ogive.Problem 21

In Problems 1316, use the frequency distributions in the problem indicated from Section 2.2 to do the following: (a) Construct a cumulative frequency distribution. (b) Construct a cumulative relative frequency distribution. (c) Draw a frequency polygon. (d) Draw a frequency ogive. (e) Draw a relative frequency ogive. Problem 22

In Problems 1316, use the frequency distributions in the problem indicated from Section 2.2 to do the following: (a) Construct a cumulative frequency distribution. (b) Construct a cumulative relative frequency distribution. (c) Draw a frequency polygon. (d) Draw a frequency ogive. (e) Draw a relative frequency ogive.Problem 31

In Problems 1316, use the frequency distributions in the problem indicated from Section 2.2 to do the following: (a) Construct a cumulative frequency distribution. (b) Construct a cumulative relative frequency distribution. (c) Draw a frequency polygon. (d) Draw a frequency ogive. (e) Draw a relative frequency ogive.Problem 32

Walt Disney Company The data on the next page represent the stock price for the Walt Disney Company at the end of each month in 2010. Construct a time-series plot and comment on any trends. What was the percent change in the stock price of Disney from January 2010 to December 2010?Date Closing Price Date Closing Price 1/10 28.71 7/10 30.72 2/10 28.99 8/10 31.55 3/10 31.34 9/10 32.68 4/10 35.01 10/10 36.13 5/10 31.00 11/10 36.51 6/10 31.36 12/10 37.51 Source: TD Ameritrade

Google, Inc. The following data represent the closing stock price for Google, Inc. at the end of each year since it first went public in 2004 until the end of 2010. Construct a time-series plot and comment on any trends. What was the percent change in Google stock from 2009 to 2010?Date Closing Price Date Closing Price 2004 192.79 2008 307.65 2005 414.86 2009 619.98 2006 460.48 2010 593.97 2007 691.48 Source: TD Ameritrade

Federal Debt The following data represent the percentage of total federal debt as a percentage of gross domestic product (GDP). The GDP of a country is the total value of all goods and services produced within the country in a given year. Construct a time-series plot and comment on any trends.Year Debt as % of GDP Year Debt as % of GDP 1991 61.17 2001 56.46 1992 64.09 2002 58.52 1993 66.17 2003 60.88 1994 66.23 2004 62.18 1995 67.08 2005 62.77 1996 66.66 2006 63.49 1997 64.97 2007 63.99 1998 62.84 2008 69.15 1999 60.47 2009 83.29 2000 57.02 2010 94.27 Source: http://www.usgovernmentspending.com/federal_debt_ chart.html

College Enrollment The data in the next column represent the percentage of 18- to 24-year-olds enrolled in college. Construct a time-series plot and comment on any trends.Year Percent Enrolled Year Percent Enrolled 1991 33.3 2000 35.5 1992 34.4 2001 36.3 1993 34.0 2002 36.7 1994 34.6 2003 37.8 1995 34.3 2004 38.0 1996 35.5 2005 38.9 1997 36.8 2006 37.3 1998 36.5 2007 38.8 1999 35.6 2008 39.6 Source: U.S. Center for Education Statistics

Rates of Return of Stocks Stocks may be categorized by industry. The following data represent the 5-year rates of return for a sample of consumer goods stocks and energy stocks ending October 20, 2010.Consumer Goods 5.51 11.42 18.09 10.26 5.82 26.38 8.33 2.57 12.07 -0.37 4.73 24.6 -1.54 9.31 7.40 10.69 14.84 0.66 6.64 -14.74 10.84 15.18 8.08 11.34 21.43 1.53 7.00 1.63 -7.48 3.45 14.73 8.62 -0.60 -1.72 36.36 Energy 3.50 2.68 4.43 3.59 20.77 16.04 15.88 9.09 3.69 14.99 15.82 3.99 14.34 17.16 -4.51 29.97 5.95 -1.29 - 9.04 11.77 11.68 6.82 12.22 10.69 16.67 8.92 2.76 14.76 2.39 -3.29 5.71 -2.55 6.06 7.39 3.90 Source: Morningstar (a) Construct a frequency distribution for each industry. To make an easy comparison, create each frequency distribution so that the lower class limit of the first class is -20 and the class width is 10. (b) Construct a relative frequency distribution for each industry. (c) On the same graph, construct a relative frequency polygon for the two industries. (d) On the same graph, construct a relative frequency ogive for the two industries. (e) Which industry appears to have the better performance for the 5-year period? Support your opinion.

American League versus National League The following data represent the earned-run average (ERA) of the top 40 pitchers in both the American League and National League in 2010. Note: ERA is the average number of earned runs given up per 9 innings. Note: Be sure to take into account the fact that the National League does not have a designated hitter. (a) Why would it be appropriate to use frequencies to compare the two leagues? (b) Construct a frequency distribution for each league. To make an easy comparison, create each frequency distribution so that the lower class limit of the first class is 2.0 and the class width is 0.50. (c) On the same graph, construct a frequency polygon for the American and National Leagues. (d) On the same graph, construct a frequency ogive for the American and National Leagues. (e) Which league appears to have better pitchers? Support your opinion. American League 2.27 3.25 3.72 4.07 4.39 2.33 3.35 3.73 4.08 4.40 2.72 3.37 3.75 4.11 4.49 2.97 3.50 3.77 4.17 4.70 3.01 3.50 3.78 4.19 4.92 3.18 3.62 3.83 4.22 4.98 3.18 3.64 3.91 4.28 5.10 3.23 3.72 3.92 4.30 5.18 National League 2.30 2.91 3.33 3.64 4.00 2.42 2.92 3.39 3.66 4.15 2.44 2.98 3.43 3.66 4.17 2.70 3.06 3.47 3.75 4.20 2.76 3.07 3.55 3.80 4.26 2.83 3.14 3.57 3.84 4.54 2.84 3.14 3.60 3.85 4.58 2.88 3.22 3.62 3.88 4.73 Source: www.mlb.com

Putting It Together: Shark! The following two graphics represent the number of reported shark attacks worldwide since 1900 and the worldwide fatality rate of shark attacks since 1900. Write a report about the trends in the graphs. In your report discuss the apparent contradiction between the increase in shark attacks, but the decrease in fatality rate.Unprovoked Shark Attacks Worldwide 00 250 300 350 400 450 500 550 600 650 100 50 0 Number of Attacks 1990s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s Worldwide Shark Attack Fatality Rate, 19002009 1990s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s Worldwide Shark Attack Fatality Rate, 19002009 Decade Source: Florida Museum of Natural History

Which do you prefer: histograms, stem-and-leaf plots, or frequency polygons? Be sure to support your opinion. Are there circumstances in which one might be preferred over another?

The cumulative relative frequency for the last class must always be 1. Why?

What type of variable is required when drawing a time-series plot? Why do we draw time-series plots?