1. Math CC7/8 – Mar. 20 Math Notebook: Things Needed Today (TNT):
Pencil/Math Notebook/Calculator/
Sample & Population 1.3
Math Notebook:
Topic: Categorical Data from Numerical Data HW: Bar Charts & Dot Plots Worksheet

2. What’s Happening Today?
Warm Up
Lesson 1.3 – Categorical vs. Numerical Data
Begin HW?

3. How many data values are within one MAD of the mean? (above or below)
Learning Check 1.2
How many data values are within one MAD of the mean? (above or below)
Write this number as a percent =
10.6 to = 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%

4. Add to notebook

5. Let’s collect our class data on these questions
Let’s collect our class data on these questions! I will record our answers on the board.

7. Question?
How might you compare results to see if each sample responded to a survey in a similar way? How can using percentages help you make comparisons?

9. Notice the 4 different samples reported:
Answers to the 1st Roller Coaster Survey question from Internet respondents
Answers to the second Roller Coaster Survey question from Internet respondents
Answers to the first Roller Coaster Survey question from 7th graders
Answers to the second Roller Coaster Survey question from 7th graders

10. Frequency of 7th graders’ response “front” is 27.

11. **Notice how the relative frequency was calculated*****
Add to notebook
**Notice how the relative frequency was calculated*****

12. As a class we answered the questions from the survey questions about the roller coaster. Make sure you copy our class vote on your worksheet.
Calculate the relative frequency (%) for each column
round to the nearest whole %
59%
43%
30%
35%
22%
11%

13. Calculate the relative frequency (%) for each column
Please continue filling in your chart and find the relative frequency for each column for the votes from the internet, 7th graders and our class.
Calculate the relative frequency (%) for each column
round to the nearest whole %
27%
20%
11%
16%
18%
19%
12% 8%
32%
37%

14. We will discuss how to make a bar graph for each of the three data sets: the Internet data, the 7th grade data, and our class data. Use percents (%) to report relative frequencies on each bar graph. You will create a bar graph of our class data ONLY on the worksheet!
Title
Scale
Labels
Now create a bar graph of the class data only

15. Now create a bar graph of the class data only

16. Which measure(s) of center – mean, median, or mode – can you use to describe these results? Explain…. C
The mode can be used to describe these results because it is a measure of center for categorical (nominal) data.

17. Online vs. 7th graders vs. class?
1) For each survey question, write 2 statement comparing results from the 3 data sets. D
Question Two:
Strongest preference?
Least important?
Online vs. 7th graders vs. class?
Question One:
First seating choice?
Last seating choice?
Online vs. 7th graders vs. class?
Both groups had “front” as their first choice. The online respondents had a stronger preference for the fornt (about 60%) than did the original sample of the 3 7th grade classes.
Both samples indicated a preference for ‘airtime’ and ‘speed’ when riding a roller coaster.

18. How are the summaries useful?
Write 2 statements to summarize the data collected from the Roller Coaster Survey.
How are the summaries useful?
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..

19. E) Suppose 400 people ride a roller coaster in one day
E) Suppose 400 people ride a roller coaster in one day. How many of them would you predict want to sit at the front? Explain.
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%.