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