Statistics 1

1. PRESENTATION OF DATA
Edward Van Martija

2. Enrolment of Students in JB University
Level Frequency Relative Frequency
Elementary
High School
College
Graduate Students
1,500
1,200
5,300
500
18
14
62
6
Total 8500 100

3. Distribution of Respondents According to
Social Class
Social Class Frequency Relative Frequency
Class A (Very Rich)
Class B (Rich)
Class C (Average)
Class D (Poor)
Class E (Very Poor)
30
50
90
40
20
13
22
39
17
9
Total 230 100

4. Graphical Form
• Pie Chart or circle graph- is a
presentation showing the proportions of
each class using the relative frequency
• Bar Graph- is a method of presenting the
data using vertical or horizontal rectangles
with the classmark or midpoints of the
bases and whose heights are frequencies.

5. Frequency Distribution of Entrance
Examinatiuon scores
Class Interval
Class
Boundaries
Frequencies <CF >CF
14-20
21-27
28-34
35-41
42-48
49-55
13.5-20.5
20.5-27.5
27.5-34.5
34.5-41.5
41.5-48.5
48.5-56.5
3
9
21
15
11
1
3
12
33
48
59
60
60
57
48
27
12
1
n=60

6. • Histogram- is a graphical presentataion of
the frequency distribution table. It looks
like bargraph wherein vertical or horizontal
rectangles overlap each other on the lower
or upper class boundaries.
• Frequency polygon- is a closed figure of
connected line segments whose endpoints
are the classmarks and the heights of the
endpoints are the frequenies

7. Central Measures for Ungrouped Data
• Mean
– the mean of the n entries from a data set is
obtained by adding up all the entreies or
elements in agiven data and dividing the by
number of entries

8. Measures of Central Tendency
– A central measure or a measure of central
tendency simply means an average.

9. Central Measures for Ungrouped Data
• Median
– the median is the middle value of the
ungrouped and arranged (either lowest to
highest or highest to lowest) data when the
number of entries is odd. When the number of
elements is even, the average of two middle
– values in the ungrouped and arranged data.

10. Central Measures for Ungrouped Data
• Mode
– the mode is referred to particulare entry with
the most number of repetitions in the given
ungrouped data.

11. Example:
• The data show the number of licensed
nuclear reactors in the United States for a
recent 15 -year period. Find mean, median
mode.
104 107 109 104 109 111 104 109 112 104 109 111 104 110
109

12. Example:
• A small company consists of the owner,
the manager, the salesperson, and two
technicians, all of whose annual salaries
are listed here (Assume that this is the
entire population)

13. STAFF
Owner
Manager
Salesperson
Technician
Orderly
SALARY
50,000
20,000
12,000
9,000
9,000

14. Weighted Mean
• The weighted mean of a variable X is
obtained by multiplying each value by its
corresponding weight and dividing the
sum of the products by the sum of the
weight.

15. Example:
Course Credits Grade
English Composition
Psychology
Biology
Physical Education
3
3
4
2
83
85
78
90