2.2 ORGANIZING QUANTITATIVE DATA

OBJECTIVE: GRAPH QUANTITATIVE DATA

Chapter 2

Review

Popular Displays of Qualitative Data

Bar Graphs

Pie Charts

Pareto Charts

Side-by-side Bar Graphs

Representing Quantitative Data

Discrete Data vs. Continuous DataDiscrete can be actual Continuous must

be in classes data or classes

Frequency TableRelative Frequency TableHistogramsStem-and-Leaf PlotDot Plot

Classes of Data

Lower class limit

Upper class limit

Class width

Open ended

Age Number

20 – 29 533

30 – 39 1147

40 – 49 1090

50 – 59 493

60 and older

110

Practice

24,028 30,641 24,293 22,123 29,798 30,507

36,726 28,960 42,345 27,610 26,356 27,837

23,584 30,063 25,929 26,409 27,033 23,567

23,889 25,900 32,637 34,570 27,275 30,397

21,677 26,317 23,528 27,865 28,188 31,251

35,411 23,301 31,527 25,307 26,902 26,684

24,169 26,102 28,557 28,365 23,753 27,149

26,314 26,922 22,581 27,750 29,683 30,288

22,252 27,508 29,600

Organizing the Data

1. Input data.

2. Set classes.

3. Construct a frequency chart.

4. Construct a relative frequency chart.

5. Construct a histogram using the TI 83.

Shape of Distribution

Uniform

Bell

Skewed Right

Skewed Left

Assignment

Page 88 7, 8, 11a, b, d, e, 12a – d, 13, 15, 22, 32a – e,

37, 43, 46

2.3 More Ways to GraphObj: Graph data with polygons and ogives

Frequency Polygonplot a point above each class midpoint equal to its frequency, then connect the dots

Cumulative Frequency Distributionadd frequency of each consecutive class

Cumulative Relative Frequency Distributionadd relative frequency of each consecutive class

Practice

The following is the number (in millions) of people by age who are covered by health insurance.

25 – 34 28.935 – 44 35.745 – 54 35.155 – 64 24.7

Construct a cumulative frequency distribution chart, a cumulative relative frequency distribution chart, and a frequency polygon.

Ogives

Frequency Ogiveline graph that connects points whose coordinates are (upper class limit, frequency)

Relative Frequency Ogiveline graph that connects points whose coordinates are (upper class limit, relative frequency)

Practice

Using the same data as before, construct a frequency ogive and a relative frequency ogive.

25 – 34 28.935 – 44 35.745 – 54 35.155 – 64 24.7

Time-Series Plot

- a line graph whose horizontal axis is measured

in time (hours, months, years) and whose

vertical axis is corresponding value at each time

2.4 MisrepresentationsObj: Identify misrepresentations and correct them

The most common misrepresentation is caused by vertical axis scaling.

Another common misrepresentation is caused when using pictures.

Good Graphics

1. Label the graph clearly.

2. Avoid distortion.

3. Avoid three dimensions.

4. Do not use more than one design in the same graphic.

Assignment

2.3 page 101 8, 13, 17, 19

2.4 page 107 1 – 4, 8 – 11

Project 1