Lecture Computing for management - Chapter 6

Business Data and
Information
Lecture 6


Summary of Previous


In the previous lecture we have learnt
 What

are the quality metrics in order to buy a
monitor from a market.


Size, resolution etc.

 Monitor

technologies
 Strain due to wrongly choosing monitors.
 How to avoid strain while using monitors.
 Video cards and sound cards


Summary of Previous


We have seen a practical to set
 the

resolution
 DPI settings of monitors.


Today’s Topics


Data
 Examples



of data and its types.

Number systems
 Decimal
 Binary





Number Systems

Bits and Bytes

How computer store data?
How computer represent data?

Today’s Topics
 ASCII
 EBCDIC
 Unicode



Information
 How

Data is Converted into Information?
 Exercises



Knowledge
Data Sources


Today’s Topics
 Direct

and Indirect Data Sources

Data Quality Matters
 Microsoft Word Practical Session



What is Data?



Data items refer to an elementary
description of things, events, activities,
and transactions that are recorded,
classified, and stored but not organized to
convey any specific meaning.



Data items can be numbers, letters,
figures, sounds, or images.


Examples of Data Items


Examples of data items are
a student grade in a class, A+, A, B+, B-, etc
 the number of hours an employee worked in
a certain week e.g. 50, 40, 60 etc.
 Time e.g. 12:30



What are the Types of Data Items?
Types of Data are
 Text
 Multimedia

sound files, avi etc.
 Numeric 0 1 2 3 4 5
 Floating 10.23 2.4578 e 25 for scientific and
engineering purposes
 Alpha Numeric A12, CIIT-Fall-001 etc.


Number System


Number Systems are used for,
 Expressing

Numbers
 A Manner of counting
 Several different number systems exists.


Decimal number system
 Used

by humans to count
 Contains ten distinct digits
 Digits combine to make larger numbers





How Computers Store Data?

As discussed in Lecture 1, a computer can
understand only 1 and 0.
 A different number system is needed other
then decimal.
 Hence it is a Binary Number System.



Binary number system


A number system that has just two
unique digits, 0 and 1
A

single digit is called a bit (binary digit)
 A bit is the smallest unit of data the
computer can represent
 By itself a bit is not very informative


The two digits represent the two off
and on states


OFFis ON orON
Bit
OFF

OFF

ON

OR
0

OR

= 1 bit
1
= 1 Byte

0

0

1

1

0

1

0

0

= 1 Byte
0

1

0

0

0

0

0

1

Byte –

Eight bits grouped together to represent a
character (an alphabetical letter, a number, or a
punctuation symbol); 256 different combinations.


Bits
1000 bits = 1 kilobit (kb)
1,000,000 bits = 1 megabit (mb)
1,000,000,000 bits = 1 gigabit (gb)



Kilobits per second (Kbps), megabits
per second (Mbps), and gigabits per

second (Gbps) are terms that describe
units of data used in measuring data
transfer rates.
•

Example: 56 Kbps modem


Bytes
8 bits = 1 Byte
1024 Bytes = 1 Kilobyte (KB)
1,048,576 Bytes = 1 Megabyte (MB)
1,043,741,824 Bytes = 1 Gigabyte (GB)
1,099,511,627,776 Bytes = 1 Terabyte (TB)



Kilobyte, megabyte, gigabyte, and
terabyte are terms that describe large
units of data used in measuring data
storage.
•

Example: 20 GB hard drive


How Computers Represent Data


In order to represent data, Text codes is

used by computer systems.
 Used

to converts letters into binary
 Standard codes necessary for data transfer


ASCII




Extended ASCII




American English symbols
Graphics and other symbols

Unicode


All languages on the planet


Representing Characters:
Character Codes
 American

Standard
Code
Information Interchange (ASCII)
 Eight

for

bits equals one character; used by
minicomputers and personal computers.


Character Codes
 Extended

Binary
Coded
Interchange Code (EBCDIC)


Eight bits equals one
mainframe computers.

character;

Decimal
used

by

Character Codes
 Unicode

– Sixteen bits equals one character;
over 65,000 combinations; used for language
symbols.

ASCII

=4
0

0

1

1

0

1

0

0

EBCDIC

=4
1

1

1

1

0

1

0

0


ASCII Table- Example
Character

Decimal

@

64

A

65

B

66

C

67

D

68

E

69

F

70

G

71

H

72

I

73

Detail of ASCII Table


Data Representation
How is a character sent from the keyboard to the
computer?
Step 1:
The user presses the letter T key
on the keyboard

Step 2:
An electronic signal for the letter
T is sent to the system unit

Step 3:
The signal for the letter T is
converted to its ASCII binary
code (01010100) and is stored in
memory for processing

Step 4:
After processing, the binary code
for the letter T is converted to an
image on the output device


What is Information?


Information refers to data that have been
organized so that they have meaning and value
to the recipient.
 For

example, a grade point average (GPA) is data,
but a student’s name coupled with his or her GPA is
information.



The recipient interprets the meaning and draws
conclusions
and
implications
from
the
information.