Samples & Populations 1.3 Learning Target: I will distinguish categorical data from numerical data. Homework: SP1.3 p. 13 – Using Spread and Center and CORRECT w/Zaption video SP 1.3 Warm Up: 1. How many data values are within one MAD of the mean? 2. within two MADs? (above or below) Write this number as a percent =

Warm Up How many data values are within one MAD of the mean? (above or below) Write this number as a percent = 10.6 to 14.26 = 16 values/30 values 53.3% How many data values are within two MADs of the mean? (above or below) Write this number as a percent = 8.77 to 16.09= 29values/ 30 values 96.6%

Information sorted into categories or groups. Categorical Data Numerical Data   Information sorted into categories or groups. (favorite movies, eye colors, birth months, etc.) Data which involves counting or measuring. (Numbers) Frequency: The number of times a specific data value occurs in a data set. (7,7,3,4,5,2: the frequency of 7’s in this set is “2.” The frequency of 4 is “1.”)

How do you find relative frequencies? p. 11 The sample sizes of Internet respondents and 7th graders are different. You can use relative frequencies – frequencies based on percentages – to compare samples of different sizes. How do you find relative frequencies? Ex: What is the frequency of people who prefer to sit on the front of the roller coaster in each sample?

97 27 50 22 18 14 165 63 Roller Coaster Seating Preferences Front Votes from Internet Relative Frequency Votes from 7th Graders Votes From Our Class Front 97   27 Middle 50 22 Back 18 14 Total Votes 165 63

Other Roller Coaster Preferences Votes from Internet Relative Frequency Votes from 7th Graders Votes from Our Class Airtime 88   31 Height 36 24 Inversion 59 29 Smooth-ness 39 12 Speed 105 57 Total Votes 327 153

Our Math Class _____ respondents

Which of the following roller coaster characteristics do you prefer Which of the following roller coaster characteristics do you prefer? You may choose more than one. Math Class _____ respondents The mode can be used to describe these results because it is a measure of center for categorical (nominal) data.

Most people like speed when they ride a coaster. Question One: First seating choice? Last seating choice? Online vs. 7th graders vs. class? Question Two: Strongest preference? Least important? Online vs. 7th graders vs. class? Most people surveyed like to ride at the front, although 7th graders like to ride the middle almost as much as the front. Most people like speed when they ride a coaster. - Summaries are helpful in order to make general conclusions about the data, although these are just samples.

About 200 people would prefer to sit in front. Votes from the web = about 59% Votes from the 7th graders = about 43% This averages to about 50%.

Samples & Populations 1.3 Did I reach my Learning Target? I will distinguish categorical data from numerical data. Homework: SP1.3 p. 13 – Using Spread and Center and CORRECT w/Zaption video SP 1.3