7th Grade Math

Chapter Study Guide and Review 481

Predictions (continued)

Use Data to Predict (Lesson 3E)

CAREERS Use the table that shows the

results of a university survey of incoming

freshmen.

Career Goal Percent

Elementary teacher 5.5%

Engineer 6.4%

33. Predict how many of the 3,775 freshmen
    would choose a career as an elementary
    teacher.


34. How many of the 3,775 freshmen would
    you expect to choose a career as an
    engineer?


35. SHOES A survey showed that 72% of
    teens bought new athletic shoes for the
    school year. Based on that survey, how
    many teens in a group of 225 bought new
    athletic shoes for the school year?

EXAMPLE 9

The circle graph



/P



:FT

Do You Have an

shows the results After-School Job?

of a survey to

which 150 students

at McAuliffe

Middle School

responded. Predict

how many of the

644 students at

the school have

after-school jobs.

Find 12% of 644.

n = 0.12 · 644 Write an equation.

= 77.28 Multiply.

So, you could predict that about

77 students at McAuliffe Middle School

have after-school jobs.

Unbiased and Biased Samples (Lesson 3F)

DANCES Mrs. Jenkins is taking a survey to

find how many students would attend a

school dance.

36. Describe the sample if Mrs. Jenkins asks
    every tenth student in the eighth grade.


37. Suppose 7 out of 12 students surveyed
    said they would attend a school dance.
    How many out of 350 students would
    be expected to attend a dance?

EXAMPLE 10 In a survey of store

customers, the owners of a grocery store

determined that 25 out of 40 customers

prefer the store brand oatmeal over the

name brand oatmeal. If there is space for

500 boxes of oatmeal, how many store

brand containers of oatmeal should the

store order?

25 out of 40 or 62.5% of the customers

prefer the store brand oatmeal.

Find 62.5% of 500.

0.625 × 500 = 312.5

The store should order about 313 boxes of

store brand oatmeal.

Lesson 3

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