intro to stats Flashcards
what is statistics?
The science of Collecting,Organising ,Presenting,Analysing and interpreting data
data
Data refers to set of values for a variable
variable
A variable is any measured characteristic that differs for different subjects
types of variables
categorical and numerical/quantitative
Levels of Measurement- NOIR
categorical: Nominal Data/ Ordinal Data
numerical: interval data/ ratio data
Nominal Data(categorical)
Naming/Labelling variables without any quantitative value. i.e. gender
Ordinal Data(categorical)
Ranked data/ Typically measure non-numeric concepts e.g. satisfaction ratings
Interval Data(numerical)
we know the order and also the differences between the values.ie. temperature/ can add or subtract
Ratio Data(numerical)
Tell us about the order, the difference in value between units and have an absolute zero.i.e. weight, income
population
All items or individuals about which you want to
reach conclusions
sample
A portion of the population selected for analysis
Why use a sample?
less costly/ less time consuming/ more practical
two types of statistics
descriptive/ inferential
Descriptive Statistics
Used to summarise the main aspects of your dataset using Tables, graphs, simple formulae
Inferential Statistics
Methods that use data collected from a sample (small group) to reach conclusions or make predictions or inferences about the population (larger group)
two general classes of descriptive statistics
Measures of central tendency/ Measures of variation/dispersion