Transcript 3.1 Frequency Tables

Statistical Reasoning
for everyday life
Intro to Probability and
Statistics
Mr. Spering – Room 113
3.1 Frequency Tables

Frequency table – usually consists of two
columns, one which lists categories and the
other lists the frequency of each category.
EXAMPLE:
Sport Participation
Sport
Tennis
Swimming
Aerobics
Volleyball
Track
Number of Participants
40
85
55
80
45
3.1 Frequency Tables

Binning – when it is impossible or impractical to
create a category for every value we bin the data
into data groups each covering a range of
possible values.
Annual Energy per Person
(millions of BTUs)
Frequency (# of
States)
200-299
300-399
400-499
500-599
800-899
1,100-1,199
TOTAL
12
24
9
2
2
1
50
3.1 Frequency Tables

Relative Frequency – the proportion or
percentage of the total frequency that falls in
that category.
Relative Frequency =
frequency in category
total frequency
3.1 Frequency Tables
Relative Frequency Table of High School GPA
HS GPA
2.2-2.39
2.4-2.59
2.6-2.79
2.8-2.99
3.0-3.19
3.2-3.39
3.4-3.59
3.6-3.79
3.8-4.00
Total
Frequency
1
6
13
7
4
9
6
7
3
56
Rel. Freq.
.02
.16
.18
.13
.09
.14
.13
.11
.05
1.01
3.1 Frequency Tables

Cumulative Frequency – the number of data
values in that category and all preceding
categories
3.1 Frequency Tables

The number of people who climbed Ayers Rock over a thirty day period
were counted and recorded as follows:
31, 49, 19, 62, 24, 45, 23, 51, 55, 60, 40, 35 54, 26, 57, 37, 43, 65, 18,
41, 50, 56, 4, 54, 39, 52, 35, 51, 63, 42.
a) Set up a stem and leaf plot, and hence calculate the cumulative
frequency by adding appropriate columns.
Stem-Leaf
Frequency (f)
0
4
1
1
89
2
2
346
3
3
15579
5
4
012359
6
5
011244
9
567
6
0235
4
Upper value
4
19
26
39
49
57
Cumulative frequency
1
1+2=3
3+3=6
6+5=11
11+6=17
17+9=26
65
26+4=30
3.1 Frequency Tables
Summary:
When do we use binning?
When it is impractical to reference every category.
When might we use relative frequency?
When we would like to know the percentage of
frequency for each category.
When might we use cumulative frequency?
When we would like to know percentile or relative
cumulative frequency.
Further summary
3.1 Frequency Tables
WHAT NOW?????
CLASS WORK: pg 96 # 5, 8, 13-19 odd