1. Data Types and Storing Data
Objectives:
Understand the different data types and their uses.
Understand the terms File, Record, Field & Key Field
Be able to identify which data types to use for a given situation.
Gain an overview of the construction of Data files.
Understand the basic construction of questionnaires

2. Database construction - A reminder
File or table(s)
Record
Field name

3. Table Design Field Record Table
A single item of data stored in a database such as age or car registration number. Each field is identified by a field name.
Record
A record is all of the information that is stored about a person or thing.
Table
A collection of records, each of which has the same structure.

4. Types of Data Text Numeric Date/Time Boolean
Allows input of any letter, number, space, punctuation mark or special character like £ % & etc.
Cannot do calculations with numbers stored as text.
Numeric
Can only be numbers.
Can be whole or decimal.
Can be formatted eg formatted to two decimal places = , formatted to currency = £
Date/Time
Must only have days, months years and time format.
Can be different layouts eg dd/mm/yy or dd/mm/yyyy
Boolean
Can only have two values; true or false (eg Yes/No)

5. Types of Data
When setting up a database of pupil records which fields could we decide to use?
Pupil registration number
Forename
Surname
DOB
House Number
Street Name
Town
County
Postcode
Phone number
School Meals
What data types will we need to set for each field?
Pupil registration number Numerical
Forename Text
Surname Text
DOB Date
House Number Number/Text if house name
Street Name Text
Town Text
County Text
Postcode Text
School Meals Boolean

6. Types of Data Pupil No Forename Surname DOB Postcode School Meals 23
Alice
Brown
14/12/89
WG12 3BR
Yes 29
Molly
Reece
12/09/88
WG12 4XV 54
Brian
Trimble
05/05/90
NE1 34Z No 77
Vivien
Jones
07/06/90
NE7 33X 88
Peter
Martinez
08/04/90
NE8 44Q
What data type do we use for date of birth?
For Postcode?
For School meals?
How many fields are there in a pupil record?
Which fields make up a pupil record?
What is the date of birth of Brian Trimble?
How many records are there in the file?

7. Storing Data
One of the most important uses of computers is for storing and analysing data.
For the computer to give you accurate information, you first have to input accurate data.
GIGO
Garbage In Garbage Out
A questionnaire is simply a list of questions on a topic.
The questions can be printed on a form to fill in, or an interviewee can ask the questions and fill in the answers.
Whichever method you use you must think carefully about the questions you ask.
Designing questions to find out precisely the information you need is an important skill.

8. Collecting Data - Methods
Observation
The best method to use if you want precise numbers.
Interviewing
The best method to use if you want a wide range of ideas and comments.
Questionnaires
A good way of collecting data when you are trying to find out facts that require no additional explanation.
You want to find out how many people visit a certain shop each day. If you ask the staff they will probably not be able to give an accurate figure as they will have been too busy working to count their customers. In this case observation would be a better way of collecting the data – sitting outside the shop and noting the number of people entering it.
You want to prepare a report for your head teacher on how life at school could be improved. Interviewing pupils in groups, to see what ideas they come up with, could be the most effective way of collecting data for this.
You are doing some market research for the school tuck shop. You want to know how often pupils use the tuck shop, how much they usually spend, and the items they buy most often. Getting every pupil to fill in a questionnaire would be a good way to do this.

9. Collecting Data
For each situation decide whether a questionnaire, observation or an interview would be the best way of collecting the data.
Finding out customers’ opinions about the taste of a new dessert.
Logging the number of lorries that pass the entrance to a primary school.
Collecting information about sporting activities.
Collecting ideas from pupils for fund-raising events.
Recording the number of males and females buying clothes from a store and collecting data about their purchases.
Finding out whether a person is the best candidate for a job.

10. Designing a Questionnaire
Decide what you want to know.
Decide who you will give the questionnaire to.
Write the first draft of your questions.
This process also forms the basis of designing interview and observation techniques.
It is important to have a clear picture of what you would like to know before you begin to create your questionnaire. This helps you to write questions that will give you that information.
Your target audience determines how you will write the questions. EG if you questionnaire is only for pupils at your school, asking whether they are married or single is not appropriate.

11. Writing the Questions What is your name? How old are you?
What are your hobbies?
How often do you play sports?
When were you born?
How much do you spend on leisure activities each week?
Which school do you attend?
What are your favourite leisure activities?
The leisure and tourism department of the local council want to find out what types of leisure facilities local people would be likely to use. They decide to send a questionnaire to every adult and school-age child in the town.
Above is a draft of the questions.
It is very difficult to write perfect questions on the first attempt. Once you have written the questions you can look at the draft critically and make any changes needed.
Can you see any ways that you would change these questions?
Do we really need to know the person’s name, people might give more honest answers if they were anonymous.
Q2 and Q5 are asking the same thing. We don’t need precise ages and people might be embarrassed to give their age. Give boxes to tick eg Under 10, 10-17, 18-30, 31-50, over 50
People could give the same answers to Q 3 and Q8. Also, they are very open questions and we could get very long answers. We could ask them to list up to 3 hobbies. For Q8 we could give them a list and ask them to rank in order of preference.
Q4 is open-ended – might exaggerate to make them appear fitter.
Q6 unlikely to know an exact figure – give options eg 0-£5, £6-£10 etc
Q7 not relevant, adults don’t attend school.
Q9 biased. It encourages people to answer YES.

12. Things to Remember When Writing Questions
Avoid asking the same thing twice.
Avoid sensitive or embarrassing questions.
How easy is it to answer the question. Give boxes to tick, where appropriate.
For quantities, how accurate do the answers need to be?
Should the question be open or closed?
Restrict the range of possible answers by giving a list.
Use ranking to find out people’s preferences.
Avoid biased questions.

13. The Final Version
Questionnaires should be neatly produced with no typing or spelling errors.
There should be a short introduction explaining who the questionnaire is for and why they want the information.
Use a different typeface for this so it stands out from the questions on the sheet.
The questionnaire should be as short as possible, so you don’t waste people’s time.

14. The Final Version Cont …
The order of the questions is important.
Start with closed questions that are easy to answer.
Next ask any more-complex questions
Finally ask more personal questions.
This way people are more likely to complete your questionnaire.
Provide enough space for the answers.
Add a note at the bottom of the questionnaire to say thank you.
Always be polite – you never know when you will need to ask them again.

15. The Final Version Cont…
Finally, give your questionnaire to a friend to complete.
What do you think?
Does anything distract you?
Are the questions clear?

16. Questions
Reword these questions so that they can be answered as accurately as possible:
How old is your eldest child?
How much frozen food do you buy from the supermarket?
How many miles do you walk every week?
Do you wash as well as cook at home?
In which age category are you?
Teenager/Middle aged/Pensioner
Explain what we mean by a ‘closed’ question.
Why do you think closed questions make people feel more comfortable at the start of a questionnaire?