Lecture 7 Flashcards
Each research question has…
A numerical answer… counts… probabilities… proportions
Inference definition
Inference is the formal name given to learning from data using statistical tools
What is the parameter?
The numerical measure of the quantity of interest in the population
- parameters are generally unknown, but can be hypothetical
- will never find the parameter
Mean of the population
Standard deviation for the population
Proportion for the population
What is a random variable
An unknown quantity that varies in an unpredictable way
Random variable once observed we refer to it as…
An observed or realised value
Notion of random variables
- random variables are represented by upper case Roman letters
- observed or realised value is represented by lower case Roman letters
What does Pr(X=x) mean?
‘The probability that the random variable X takes the value x’
Random variables are describes by
Probability distubutions
Observed values of random varieables are
Data
Random variables are describes by_______
Observed values of random variables are_____
-probability distubutions
-data
What is a statstic?
A numerical summary of data
What is an estimate
- a special kind of statistic used an as intelligent guess for a parameter
Often estimates are denoted by adding a circumflex…
Û is an estimate of the parameter U
What is used to denote the parameter of U
x is a statistic and an estimate; U is a prarmeter
Yep
What is a statistical model
A mathematical description of the way the data are generated
What is the statistical model expressed in terms of?
- parameters (Greek characters)
- random variables (capitals)