CHAPTER 1 Flashcards
what is quantitative data?
- numerical observations or measurements
- can be continuous or discrete
what is qualitative data?
- non- numerical observations
what is continuous data?
- can take any value on a continuous numerical scale, e.g. height
what is discrete data?
- can only take particular values on a continuous numerical scale
what is categorical data?
- data that can non- overlapping categories
what is ordinal data?
- data which can be written in order and given a numerical rating scale
what is bivariate data?
- involves pairs of related data
what is multivariate data?
- involves sets of three or more related data values
what is primary data?
- data collected firsthand
what is secondary data?
- data which someone else has collected
what is a population?
- everything or everybody that could possibly be involved in an investigation
what is a census?
- a survey or investigation with data taken from every member of a population
when is a sample biased?
- when it is not representative of the entire population
- a sample which is collected unfairly or is too small can count as bias
what is the sampling unit?
- the people or items that are going to be sampled
what is the sampling frame?
- a list of all the sampling units
what is the Peterson capture- re capture formula?
N= Mn/m
- N= population
- M= members of population
- n= sample size
- m= number marked
what assumptions are made in the Peterson capture- recapture formula?
- the population has not changed (no births or deaths)
- the probability of being caught is equal for all of the individuals
- marks or tags are not lost/ washed off and are always recognisable
- the sample size is large enough to be representative of the population
what is a random sample?
- everyone in the population has an equal chance of being chosen
- unbiased and representative of the entire population
what is judgement sampling?
- using you judgement to select a sample which is representative of the population
what is opportunity sampling?
- using the people or objects which are available at the time to conduct a sample
what is cluster sampling?
- when the data naturally splits into groups. e.g. geographical areas
- the list of clusters is the sampling frame, some clusters are randomly selected from it to make the sample
what is systematic sampling?
- take a starting point from the sampling frame at random, then choose items at regular intervals
- for example, every 10th person on a list
what is quota sampling?
- group the population by characteristics such as age/ gender and interview a quota number from each group e.g. 10 males over 25, 15 females aged 35-60
what is a stratified sample?
- contains members of each stratum in proportion to the size of that stratum, the sample from each stratum is selected randomly
stratified sample equation?
(amount of students in stratum/ total population) x sample size
what does repeating an experiment and coming out wit the same result show you?
- the data is likely to be valid and reliable
what is a questionnaire?
- a set of questions designed to obtain data
what is the person completing a questionnaire called?
- the respondent
what is an open question?
- has no suggested answers
what is a closed question?
- has a set of given answers to chose from
issues with an open question?
- every respondent could give a different answer, so it can be difficult to summarise and analyse the answers
what to include in questionnaires?
- questions with short and simple language
- avoid biased questions
- ensure intervals do not overlap
- ensure it includes all possible answers
- include time frame
- avoid questions which respondents are unlikely to answer honestly
what is a pilot survey?
- a survey conducted on a small sample to test the design, method and reliability of that survey
what is an outlier or anomalous data value?
- value which does not fit the pattern of the data
- you can ignore the outlier if it is due to a measuring or recording error
what is a random response method?
- uses a random event to decide how to answer the question
what is cleaning data?
- identifying and either correcting or removing inaccurate data values (caused by recording or other errors) or extreme values
- removing units or other symbols from data
- deciding what to do about missing data
what is an extraneous variable?
- variables which you are not interested in but could affect the result of your experiment
what is a control group?
- tests the effectiveness of a treatment
- use random selection to select two groups of people
- give the test group the treatment and the control group no treatment
- compare the results of the two groups to see how effective the treatment is
what is a matched pair test?
- where two groups of people are used to test the effects of a particular factor
- 2 individuals with everything in common are paired up, except the thing being tested
what is a hypothesis?
- an idea that can be tested by collecting and analysing data
