Collecting Data Flashcards
What are the 4 stages of the data handling cycle?
- Specify the problem and plan. This will lead to deciding upon a hypothesis.
- Collect data from a variety of sources.
- Process and represent data.
- Interpret and discuss data.
What is a hypothesis?
A statement that it is thought might be true.
What does primary data include?
- Raw data.
- Surveys.
- Questionnaires which may have more than two categories.
- Investigations.
- Experiments
What does secondary data include?
- Databases.
- Published statistics.
- Newspapers,
- Internet pages.
What is a quantitative variable?
A variable that takes numerical values, for example, counts, temperatures, weights, amounts of money.
What is a qualitative variable?
A variable that does not take numerical values, for example, eye colour, favourite name.
What is discrete data?
Data that can only take certain numerical values in a given range, for example number of people.
What is continuous data?
Data that can take any numerical value within a range, for example height.
What is categorical?
Hair colour.
What is rank?
Grades.
How can the class width be calculated?
class width = (max value - min value) / number of classes.
What is the class interval?
The size of each class into which a range of a variable is divided, as represented by the divisions of a histogram or bar chart.
What is bivariate data?
Data that involve two variables.
Define: Population.
Everybody or everything that could be involved in an investigation.
Define: Census.
A census obtains information about every member of a population.
What are the advantages of a census?
- Unbiased.
- Accurate.
- Takes the whole population into account.
What are the disadvantages of a census?
- Time-consuming.
2, Expensive. - Difficult to ensure the whole population is used.
- Lots of data to handle.
What are the advantages of a sample?
- Cheaper.
- Less time-consuming.
- Fewer data to be considered.
What are the disadvantages of a sample?
- Not completely representative.
2. May be biased.
What should I think about when collecting primary data?
- Whether to use a questionnaire.
2. Whether you can count or measure the results.
What should I think about when collecting secondary data?
- Whether you can get exactly the information you need.
- How reliable the source is.
- Whether the data has been collected by someone who is biased.
What is a sampling frame?
A list of the population.
What is a sample?
Part of the population.
What are the advantages of convenience sampling?
Easy.
What are the disadvantages of convenience sampling?
It can be biased.
What is convenience sampling?
A convenient sample that is used when it is only possible to take a sample in a particular way, or time may be too short to use most sampling methods.
What is quota sampling?
Pre-specified numbers of the population are taken with certain combinations of characteristics such as sex, age etc.
What is the advantage of quota sampling?
Easy.
What is the disadvantage of quota sampling?
Can be biased.
What is cluster sampling?
A sample of the groups is selected randomly and observations are taken from each member of these groups.
What is the advantage of cluster sampling?
Easy.
What is the disadvantage of cluster sampling?
Can be biased.
What is systematic sampling?
Every nth person or unit on an unordered list is selected, beginning at a random point.
What is the equation for systematic sampling?
population / sample size
How can a random sample be found?
(Ran) x (population)
What is stratified sampling?
A sampling method that reflects the proportion of the population in each group.
What is the formula for stratified sampling?
( (members in group) / (population) ) x sample size
When conducting a questionnaire, what are the advantages of giving out a form?
- It’s easy to give out a lot to people.
- Giving it out and collecting it is not a lot of work.
- It’s cheap.
- People can take their time.
When conducting a questionnaire, what are the disadvantages of giving out a form?
- You won’t know if someone has misunderstood a question or written an answer down wrongly.
- People might miss questions out.
- They might not bother to do it or return it.
When conducting a questionnaire, what are the advantages of doing an interview?
The interviewer can make sure people understand the questions and answer them all.
When conducting a questionnaire, what are the disadvantages of doing an interview?
- It takes a lot of time.
2. If you’re paying someone to collect the data for you it will be expensive.
When conducting a questionnaire, what is the problem with non-response?
The sample should represent the population fairly. If you don’t get a return from someone it will bias the results.
When conducting a questionnaire, how can the response rate be improved?
- By including a reply envelope, with freepost or a stamp.
2. Some companies enter people into a prize draw as an incentive.
When conducting a questionnaire, what are the advantages of giving out a form?
- It’s easy to give out a lot to people.
- Giving it out and collecting it is not a lot of work.
- It’s cheap.
- People can take their time.
When conducting a questionnaire, what are the disadvantages of giving out a form?
- You won’t know if someone has misunderstood a question or written an answer down wrongly.
- People might miss questions out.
- They might not bother to do it or return it.
When conducting a questionnaire, what are the advantages of doing an interview?
The interviewer can make sure people understand the questions and answer them all.
When conducting a questionnaire, what are the disadvantages of doing an interview?
- It takes a lot of time.
2. If you’re paying someone to collect the data for you it will be expensive.
Why should a pilot survey be done before conducting a questionnaire?
A pilot survey helps check that the questions are clear and that all the necessary information will be obtained.
How can a pilot survey be conducted?
By giving the questionnaire to a small group of people then using their responses to fine tune the questionnaire.
Why is a placebo used in statistical experiments?
To eliminate any psychological factors.
What kind of questions should be asked in a questionnaire?
- Don’t ask biased questions i.e. leading questions.
- Don’t ask embarrassing questions.
- Give people a choice of answers i.e. closed questions.
- Think about using an opinion scale.
- Make sure questions are not open to interpretation.
