Transcript 2 - wsdsecondarymath

Journal Writing
Warm-Up
Bell Quiz 1-4
Using the key: H = Hockey, B =
Badminton, F = Football, each letter
below indicates a student joining the
sports club.
HHBFBHFFHB
BBHFHHFBHB
a) Construct a frequency table for
the data.
b) Determine which club has the
highest frequency and which club has
the lowest frequency.
c) Calculate the percentage of
students who joined the Hockey club.
d) Explain how a frequency table can
give you a quick picture of your data.
This, That or the Other
Using Frequency Tables to Examine Data
Words to Know
 Categorical Data –
 Conditional Relative Frequencies –
 Joint Frequency –
 Marginal Frequency –
 Trends -
 Two-Way Frequency Table -
Categorical vs. Numerical Data
Data can be numerical or categorical. Try to figure
out what each of the following are:
 How many pets do students in our class have?
 How many hours a week do we spend watching TV?
 What is our favorite sport?
 What kind of music do we like best?
 How many hours a week do we talk on the phone?
 What kinds of snacks do we like?
 How much do our backpacks weigh?
 How much candy do we eat each week?
What type of data we have
determines how we examine it.
Categorical
Numeric
 Frequency tables
 Box and Whisker Plots
 Dot Plots or pictographs
 Histograms
 Bar Graphs
 Scatter Plots
Extending Frequency Tables
Frequency Tables can show more than just a total for each
category. They can be extended to show relative
frequency.
Relative Frequency can be expressed as a fraction,
decimal or a percent.
¼
.25
25%
Let try it.
 Twenty students were asked how many hours they worked
per day. Their responses, in hours, are listed below:
 5; 6; 3; 3; 2; 4; 7; 5; 2; 3; 5; 6; 5; 4; 4; 3; 5; 2; 5; 3
 Below is a frequency table listing the different data values in
ascending order and their frequencies. Copy this table.
 Calculate the Relative Frequency and write in a new column.
C:\Users\sg\Pictures\2011-0725_1546.png
# of
hours
worked
# of
students
in each
category
I’ll be coming around to check
your work, then we’ll share!
What if we wanted to see how the hours worked data
compares with the students test grade.
To do this we can make a two-way frequency table to show
the joint frequencies.
Grade
Hours
A
B
C
D
F
2
2
1
0
0
0
3
1
2
1
1
0
4
0
1
2
0
0
5
1
1
3
1
0
6
0
0
1
0
1
7
0
0
0
1
0
Do you notice any trends in the data?
Marginal Frequencies are the
totals of each row and column.
Grade
Hours
A
B
C
D
F
Total
2
2
1
0
0
0
3
3
1
2
1
1
0
5
4
0
1
2
0
0
3
5
1
1
3
1
0
6
6
0
0
1
0
1
2
7
0
0
0
1
0
1
Total
4
5
7
3
1
20
Both totals must add up to
the total number of students
So how do we look at the relative frequencies
of a two-way freqency table?
Grade
Hours
A
B
C
D
F
Total
2
1/10
.10
10%
1/20
.05
5%
0
0
0%
0
0
0%
0
0
0%
3/20
.15
15%
3
1/20
.05
5%
1/10
.10
10%
1/20
.05
5%
1/20
.05
5%
0
0
0%
1/4
.25
25%
4
5
6
7
Total
Ok, now you finish putting in the
Conditional Relative Frequencies.
Homework
Frequency Tables
Worksheet