Chapter 2.1 Organizing Data

Raw Data – original form ABBABO OOB B BBOAO AOOO AOBA Distribution of Blood Types of 25 army inductees

Frequency Distribution A frequency distribution is the organization of raw data in table form, using classes and frequencies. Each raw data value is placed into a quantitative or qualitative category called a class. The frequency of a class then is the number of data values contained in a specific class.

Categorical Frequency Distributions The categorical frequency distribution is used for data that can be placed in specific categories (nominal and ordinal)

Frequency Table – Blood Types ClassTallyFrequencyPercent

Try it! – Pg. 102 #1 ClassTallyFrequencyPercent

Grouped frequency Distributions When the range of the data is large, the data must be grouped into classes that are more than one unit in width, in what is called a grouped frequency distribution. Class limits – upper class limit, lower class limit Class width – range Class boundaries are used to separate the classes so that there are no gaps in the frequency distribution

About classes….. 1.There should be between 5 and 20 classes 2.It is preferable, but not necessary that the class width be an odd number. This ensures that the midpoint of each class (the class midpoint) has the same place value as the data 3.The classes must be mutually exclusive 4.The classes must be continuous 5.The classes must be exhaustive 6.The classes must be equal in width

Ages of the 50 wealthiest people in the world: Lower Class Limit: 2.Upper class Limit: 3.Class width: 4.Class limits:

Create a frequency table for the 50 wealthiest people in the world using 8 classes Class LimitsClass Boundaries TallyFrequencyPercent

Create a grouped frequency distribution for the data using 7 classes: These data represent the record high temperatures in degrees Fahrenheit for each of the fifty states

Frequency Table: High Temperatures Class LimitsClass Boundaries TallyFrequencyPercent

Ungrouped Frequency Distribution Used when the range of the data values is relatively small. Uses single data values for each class: The data shown represents the number of miles per gallon that 30 selected SUVs obtained in city driving

Frequency Table: MPG of SUVs Class Limits Class Boundaries TallyFrequencyPercentCumulative Frequency

Cumulative Frequency A cumulative frequency distribution is a distribution that shows the number of data values less than or equal to a specific value (usually an upper boundary)

Try it! Applying the Concepts Pg. 45 #1-7