Intro Flashcards
What infographic do you never use
Pie charts
Statistics
Statistics is the branch of mathematics that examines ways to process and analyse data. Statistics provides procedures to collect and transform data in ways that are useful to business decision makers. To understand anything about statistics, you first need to understand the meaning of a variable.
4 fundamental terms of statistics
Population
Sample
Parameter
Statistic
Population
A population consists of all the members of a group about which you want to
draw a conclusion.
Sample
A sample is the portion of the population selected for analysis
Parameter
A parameter is a numerical measure that describes a characteristic of a
population (measures used to describe a population) GREEK LETTERS REFER
TO A PARAMETER
Statistic
A statistic is a numerical measure that describes a characteristic of a sample
(measures calculated from sample data) ROMAN LETTERS REFER TO
STATISTICS
2 types of statistics
Descriptive statistics
Inferential statistics
Descriptive statistics
Collecting, summarising and presenting data
Inferential statistics
Drawing conclusions about a population based on sample
data/results (i.e. estimating a parameter based on a statistic
3 steps of descriptive statistics
Collect data
Present data
Characterise data
Collect data example
Survey
Present data example
Tables and graphs
Characterise data example
Sample mean
Steps of inferential statistics
Estimation
Hypothesis Testing
Estimation example
Estimate the population mean weight (parameter) using the
sample mean weight (statistic)
Hypothesis testing example
Test the claim that the population mean weight is 100 kilos
4 important sources when collecting data
Data distributed by organisation or individual
Designed experiment
Survey
Observational study
2 classifications of data sources
Primary
Secondary
2 types of data
Categorical (defined categories)
Numerical (quantitative)
2 types of numerical variables
Discrete (counted items)
Continuous (measured characteristics)
Categorical data
Simply classifies data into categories (e.g. marital status, hair
colour, gender)
Numerical discrete data e.g.
Counted items – finite number of items (e.g. number of
children, number of people who have type-O blood
Numerical continuous data e.g.
Measured characteristics – infinite number of items
e.g. weight, height
4 levels of Measurement and Measurement Scales from highest to lowest
Ratio data
Interval data
Ordinal data
Nominal data
Ratio data
Differences between measurements are meaningful and a true zero
exists
Interval data
Differences between measurements are meaningful but no true zero
exists
Ordinal data
Ordered categories (rankings, order or scaling)
Nominal data
Categories (no ordering or direction)
Ratio data eg
Height, weight, age, weekly food spending
Interval data eg
Temperature in degrees Celsius, standardised exam score
Ordinal data eg
Rankings in a tennis tournament, student letter grades, Likert
scales