Algebra 1 Common Core Student Edition, Grade 8-9

Are the data numerical
measurements?
Movie titles and jersey
numbers are not numerical
measurements, but a
number of students is.

Classif y in g D at a

Is each data set qualitative or quantitative?

Q favorite movies

The data are not numerical quantities. These are qualitative data.

0 numbers of students in different schools who take Spanish

The data are numerical quantities. These are quantitative data.

0 football jersey numbers

The data are numerical but not measurements. They are qualitative data.

vj Got It? 1. Is each data set qualitative or quantitative? Explain.

a. costs of CDs b. eye colors

i

Does the data set

involve one or tw o

variables?

One variable means the

data set is univariate.

Two variables means the

data set is bivariate.

The kind of data you are working with determines the type of graph you use to display

the data. A set of data that uses only one variable is univariate. A set of data that uses

two variables is bivariate.

Id ent if ying Typ es o f Dat a

Is each data set univariate or bivariate?

Q the atomic weights of the elements in the periodic table

There is only one variable, atomic weight. The data set is univariate.

0 the edge lengths and volumes of cubes

There are two variables, edge length and volume. The data set is bivariate.

Go t It? 2. Is each data set univariate or bivariatel Explain.

a. heights and weights of mammals

b. the cost of Internet service from several different providers

Statisticians collect information about specific groups of objects

or people. The entire group that you want information about is

called a population. When a population is too large to survey,

statisticians survey a part of it to find characteristics of the whole.

The part that is surveyed is called a sam p l e.

Three sampling methods are shown on the next page. When designing

a survey, you should choose a sample that reflects the population.

754 Ch ap t e r 12 Data Analysis and Probability