How Can I Practice 2.1 – 2.4? Pp 175-179 #1-6
1. The number line in the following graphic represents net exports in billions of dollars for six countries. Net
exports are obtained by subtracting total imports from total exports; a negative net export means the
country imported more goods than it exported.
The World of
Exports
a. Estimate the net amount of exports for Japan. Is your answer a positive or negative integer? Explain what
this number tells you about the imports and exports of Japan.
.
b. Estimate the net amount of exports for the United States. Is your answer a positive or negative integer?
Explain what this number tells you about the imports and exports of the United States.
c. What is the difference between net exports from Japan and Italy?
d. What is the difference between the net exports from Britain and France?
e. What is the total sum of net exports for the six countries listed?
2. In the bar graphs below, a projection of world population by age groups and gender for six different
regions is given as a percent of the region's population at the time.
Population Pyramids for Regions and Selected Countries: 2002 and 2050 In 2050, the
elderly are expected to be a substantially larger part of national and regional populations.
a. In 2002, which region had the largest portion of its population in the 0-4-year-old
age group, and what was that percent?
b. What is the 2050 projection for the 10-14 age group of the region you identified in
part a?
c. In 2002, which region's 80+ age group is larger than the 75-79 age group?
In 2050, how many such regions are projected?
How could you explain this phenomenon?
d. In most regions, by 2050 the various age groups have become fairly equal in size,
except perhaps for the oldest age groups. Which region does not appear to follow
that trend?
e. Which two regions are projected, in 2050, to have larger populations of 60-64year-olds than 45-49-year-olds?
f. In 2002, which region had pretty much equal numbers in the 0-39 and 40-80+ age
groups?
g. In Sub-Saharan Africa, the projected size of the elderly population will remain quite
small in 2050, compared to every other region. What single factor do you think
might be most responsible?
3. The educational attainment of Texans 25 and older in 2003 is summarized below.
Education
Less than 9th grade
9th to 12th grade, no diploma
High School Graduate
Some college, no degree
Associate’s degree
Bachelor’s degree
Graduate or professional degree
Attained by
1.416.434
1,516,837
3,473,633
2,773,964
778,403
2,163,749
1,065,672
Identify each category on the circle graph.
4. On an average winter day in Chicago, the AAA receives 125 calls from people who need help
starting their cars. The number of calls varies, however, depending on the temperature. Here is
some data giving the number of calls as a function of the temperature (in degrees Celsius).
Temperature (ºC)
-12
-6
0
4
9
Number of auto club service calls
250
190
140
125
100
a. Sketch the given data on an appropriately scaled and labeled coordinate axes.
b. Use your graphing calculator to determine the equation of the regression line for the data in the
preceding table.
c. Use your regression equation form part b to determine how many service calls the AAA can expect if
the temperature drops to -20º C.
5. A coach of a local basketball team decides to analyze the relationship between his players’ height and
their weights.
Player
1
2
3
4
5
Height (in.)
68
72
78
75
71
Weight (lb)
170
210
235
220
175
a. Use your graphing calculator to determine the equation of the regression line for this data.
b. Player 6 is 80 inches tall. Predict his weight.
c. If a players weights 190 lbs., how tall would you expect him to be?
6. Collect data of 10 students in your class. Measure each students’ wrist size and neck circumference.
Use your calculator to produce a scatterplot for wrist circumference versus neck .
Student
1
2
3
4
5
6
7
8
9
10
Wrist Circumference (in)
Neck Circumference (in.)
a. Does there appear to be a linear relationship?
b. Determine the regression line for this data with your calculator.
c. Use your regression line to model to predict the neck circumference for someone whose wrist
circumference is 7.5 inches.