Chart 1 Exercises
Percentage
of the World’s Population With and
Without Access to Safe Water, 1990–96 
1. Study Chart 1, which shows world population
and access to safe water and answer the following questions.
 What percentage
of the world’s population in 1990–96 did not have access
to safe water?
 The total population
of the world in 1998 was approximately 5.9 billion. If the percentage
of people with access to safe water stays the same as it was in 199096,
use your answer to question 1a and calculate how many people were
without safe water in 1998? (Divide the percentage by 100 to get a
decimal, then multiply the total population of the world by the decimal
figure).
 How many people
did have access to safe water?
2. In the year 2015,
the population of the world is projected to reach 7.1 billion.
 If the number
of people with access to safe water stays the same as it was in 1990–96,
what percentage of the world’s population in 2015 will have access
to safe water? (Divide 4.42 billion by 7.1 billion and multiply by
100.)
 How does this
percentage compare with that shown in Chart 1? Based on this information,
would the population in 2015 be better off, worse off, or the same?
Explain.
3. Statistics can
be powerful tools that help us understand our world. But statistics
must be used carefully, and people must understand what the data do
and do not tell us.
It is the year 2000.
You are running for reelection after two fiveyear terms as mayor of
a city of 800,000 people. In 1990, the population was 600,000, and at
that time 37 percent of the population in the city had access to safe
water. In the year 2000, 40 percent of the population in the city now
have access to safe water.
 Did the percentage
of population with access to safe water and sanitation increase or
decrease during your time as mayor? By how much?
 Calculate the
number of people with access to safe water in 1990. Calculate
the number of people with access to safe water in 2000. Did the number
of people with access to safe water increase or decrease during your
time as mayor. By how much?
 Did the number
of people without access increase or decrease? (Find the percentage
of the population without access by subtracting the percentage
of the population with access from 100%, convert the percentage
into a decimal, and then follow the calculations you used in question
2b.)
 As mayor, what
can you say to voters about the progress you have made in the area
of safe water and sanitation?
 What might your
challenger say to voters about the lack of progress you have
made?
 What can happen
if statistics are not used carefully?
 What kinds of
problems might make it difficult to provide safe water to people in
urban areas where populations are growing rapidly?
