U2T2 - Data + Information

Question 1

What is data?

Answer 1

Raw facts + figures which are out of context + therefore meaningless. A random set of digits.

Question 2

What is information?

Answer 2

Raw facts and figures that are processed + have context and therefore meaning.

Question 3

What is knowledge?

Answer 3

Understanding + consequences placed on information.

Question 4

What are the 6 terms that we need to decipher high quality info from low quality info?

Answer 4

Accurate, Up to Date, Relevant, Complete, Effectively presented + reliable.

Question 5

How might inaccurate data occur?

Answer 5

Poorly worded questions which lead to inaccurate answers, not enough sources, manual data entering mistakes, incorrectly calibrated instruments. E.g. Transcription error.

Question 6

Why is up to date data so important for information quality?

Answer 6

Can be misleading or incorrect as information changes over time e.g. Change of address

Question 7

Why is relevant data so important for high quality information?

Answer 7

It cannot be useful if it is irrelevant. E.g. Unnecessary details.

Question 8

Why is complete data so important for information quality?

Answer 8

If part of info is missing, you cannot fully understand and take in the whole picture. E.g. A field is left out.

Question 9

Why is effectively presented data so important for information quality?

Answer 9

If it is disorganised it is hard to understand and so becomes less useful. e.g alphabetical order for class lists.

Question 10

Why is reliable data so important for information quality?

Answer 10

Sources that aren’t reliable can be prone to error so may be inaccurate and therefore low quality.

Question 11

What is verification?

Answer 11

Use of checks to ensure data is high quality + accurate. It confirms the integrity of the data as it’s copied between diff parts of computer system.

Question 12

What can verification be used for?

Answer 12

Ensure data in database contains no mistakes when transferring data from original source.

Question 13

When can verification take place?

Answer 13

When data is entered at the human-machine interface + when copied between other components within computerised system.

Question 14

Explain the purpose of a key field?

Answer 14

To be unique to only one data subject so it distinguishes from others + also provides a link between tables.

Question 15

Explain how a check digit can be used to detect a transposition error?

Answer 15

When the product code is entered, the system calculates the check digit + ensures they are both the same. If not, an error is flagged. A transposition error is when the places of 2 digits are interchanged. The weightings will not be accurate for each number in the code so the check digits will not match.

Question 16

3 examples of data verification?

Answer 16

Double entry, proof reading + check digits.

Question 17

Describe double entry verification.

Answer 17

The field must be entered twice to ensure that the typist has not made a mistake. E.g transposition. If not matched, an error is flagged.

Question 18

Describe proof reading verification.

Answer 18

You must read over the data and confirm it is accurate before confirming it.

Question 19

Describe check digit verification.

Answer 19

Extra digits added to a number code. They are worked out by modulus 11 arithmetic and reduce errors. E.g. Transposition.

Question 20

How might you calculate a check digit? E.g. 1234x

Answer 20

1234 - product code
5432 - weightings
30 - total
2r8 - /11
11 - 8 = 3 (Check digit)

Question 21

What 2 extra errors might occur in batch processing?

Answer 21

A document may be missed out or the data on the document may be entered twice.

Question 22

What is batch processing?

Answer 22

Entering a large number of documents at once e.g. Using a scanner.

Question 23

What is a batch total?

Answer 23

Total value of 1+ fields in a data batch. Calculated manually + then checked with computer total. E.g. Number of documents.

Question 24

What are control totals?

Answer 24

Batch totals with a meaningful value e.g. Number of documents or transactions.

Question 25

What are hash totals?

Answer 25

Batch totals with no meaning. E.g. Total of all numeric fields for a certain record (employee number)

Question 26

What can hash totals be used to spot?

Answer 26

Missed or doubly entered documents, one document entered twice whilst one missed.

Question 27

What is data validation?

Answer 27

Automatic checking of data entered into computer system to reduce errors. Sensible, reasonable, within suitable boundaries + complete.

Question 28

Examples of validation checks?

Answer 28

Range, presence, length, format, type, lookup, check digit.

Question 29

What is a range check?

Answer 29

Rejects data outside 2 limits. E.g. Age 11 to 18. Error is flagged if not between these.

Question 30

What is a presence check?

Answer 30

Ensures no fields are missed out when entering data, and error is flagged if data is missing. E.g. No name

Question 31

What is a length check?

Answer 31

Ensures is of a reasonable number of characters e.g. A name between 2 and 20 characters long.

Question 32

What is a type check?

Answer 32

Ensures data is of a certain data type. E.g. Number of items in stock should be an integer.

Question 33

What is a format check?

Answer 33

Ensures data matches a certain pattern e.g. Email address (local part, @sign + domain/host name) or postcode

Question 34

What is a lookup check?

Answer 34

Ensures data matches one of a list of valid entries e.g. Miss, Mr, Dr + Mrs.

Question 35

How might you validate data through Access? (3)

Answer 35

Validation rule property, data types + required property.

Question 36

What is validation rule property in Microsoft Access?

Answer 36

Set a validation rule so data input must follow a certain rule. E.g. Junior/Freshman must be JR/FR, an error message appears if entered incorrectly.

Question 37

How might you use data types for validation in Microsoft Access?

Answer 37

Restrict data types used by requiring certain type e.g. Text.
Input mask may specify how a postcode is entered.

Question 38

How might one use required property in Microsoft Access?

Answer 38

Avoid empty fields, prompted with error message to enter data before continuing.