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) 10.6 to 14.26 = 16 values/30 values
Write this number as a percent = 53.3%
How many data values are within two MADs of the mean?
(above or below) 8.77 to 16.09= 29values/ 30 values
Write this number as a percent = 96.6%
p.11
Categorical Data
Information sorted
into categories or
groups.
Numerical Data
Data which involves
counting or measuring.
(Numbers)
(favorite movies, eye colors,
birth months, etc.)
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.”)
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?
Roller Coaster Seating Preferences
Preference
Votes from Relative Votes from Relative Votes From Relative
Internet Frequency 7th Graders Frequency Our Class Frequency
Front
97
27
Middle
50
22
Back
18
14
Total
Votes
165
63
Other Roller Coaster Preferences
Preference
Votes from Relative Votes from Relative Votes from Relative
Internet Frequency 7th Graders Frequency Our Class Frequency
Airtime
88
31
Height
36
24
Inversion
59
29
39
12
105
57
327
153
Smoothness
Speed
Total
Votes
Our Math Class
_____ respondents
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.
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