Algebra 1 Common Core Student Edition, Grade 8-9

Fr e q u e n cy an d

Histograms

S- I D. A. 1 Rep r esen t d at a w i t h p l o t s o n t h e r eal n u m b er

line (dot plots, histograms, and box plots). Also N-Q.A.1

M P1, MP 2, M P3, M P4, MP 6

Co m m o n Co r e St at e St a n d a r d s

Object ive To make and interpret frequency tables and histograms

Get t in g Read y!

Yo u can m ak e

assumpt ions t o

help you est im at e

so l ong as yo u

realize that

you may need

to change your

assum pt i ons i f

you g et b et t er

information.

As part of an environmental science p ro ject,

you measure t he t rees in a park to t he nearest

foot. Your data are shown at the right. You

want to est im at e t he number o f t rees between

30 f t and 60 f t t all. Choose a method fo r

estimating and st at e any assumptions you make.

What is your estimate? Explain your reasoning.

mathematical Esse n t i a l U n d e r st a n d i n g There are many ways to organize and visually display

PRA CTI CES data. Sometimes it is helpful to organize numerical data into intervals.

Lesso n

Vocabulary

frequency

frequency table

histogram

cum ulat ive

frequency table

How do you choose

intervals?

The data values range

from 2 to 17, so there

are a total of 16 possible

values. You can divide

these 16 values into 4

intervals of size 4.

The frequency of an interval is the number of data values in that interval. A frequency

table groups a set of data values into intervals and shows the frequency for each

interval. Intervals in frequency tables do not overlap, do not have any gaps, and are

usually of equal size.

Pr o b l em 1 Making a Frequency Table

Baseb al l The numbers of home runs by the batters in a local home run derby

are listed belowi What is a frequency table that represents the data?stea belowj wnat is a trequency tame t

y( 3 ^ 4 /

The minimum data vakie is 2 and the maximum is 17.

Intervals of 4 seem reasonable. In the first column of the

table, list the intervals. Count the number of data valuesA

in each interval and list the number in the second

column.

Go t It? 1. What is a frequency table for the data in

Problem 1 that uses intervals of 5?

Home Run Resul t s

2-5 4

6-9 4

10-13 3

14-17 3

732 Chapter 12 Data Analysis and Probability