Statistics Flashcards
Descriptive statistics
Large amounts of data summarised and presented to the public in a way that they can understand
Inferential statistics
Asking a small number and then predicting an outcome based on those responses
Types of data
Categorical (cannot be answered with numbers)
Numerical
Types of categorical data
Ordinal (can be ordered eg grades)
Nominal (cannot be ordered eg eye colour)
Types of numerical data
Continuous (may be any one of an infinite amount of numbers eg height)
Discrete (can only be chosen from a certain set of values eg shoe size)
What is primary data
Collected by the person that will use it
What is secondary data
Not collected by the person who is going to use it eg via newspaper, books, internet
Population
Entire group being studied
Sample
A group that is selected from the population in order to gather information
Census
Survey of the whole population
Unit
Individual member of the population
Bias
Something that might distort data so there will not be a correct representation of the sample
Outlier
An individual that falls outside of the overall pattern
Sampling methods
Simple random sampling
Stratified random sampling
Cluster sampling
Quota sampling
Simple random sampling
Sample size is selected from a population and everyone in the population has an equal chance of being picked
Stratified random sampling
First popukation is divided into subgroup (age, gender, socio-economic status etc)
Then samples are drawn from each subgroup
Cluster sampling
Population divided into clusters
Some clusters are randomly chosen
Quota sampling
Non probability technique
Sample has the same proportion of individuals in population eg ratio of girls in population to girls in sample
Data handling cycle
Pose a question
Collect data
Present and analyse data
Interpret results
Types of Survey
Face to face Telephone Postal questionnaire Online questionnaire Observation
Ways to graph data
Scatter plot Pie chart Frequency table Bar chart Line of best fit Line plot Histograms Stem and leaf
Types of data distribution
Symmetric
Negatively skewed/skewed left (positive slope)
Positively skewed/ skewed right (negative slope)
What is a response variable
What axis
Any factor that can influence
Y
What is explanatory variable
What axis
Question that we ask in our study
X
Types of correlation on scatter graphs
Perfect positive correlation (strong) High positive correlation Low positive correlation (weak) No correlation Low negative correlation(weak) High negative correlation Perfect negative correlation (strong)
