Transcript Ex St 801 Statistical Methods

Ex St 801
Statistical Methods
Introduction
Basic Definitions
STATISTICS:
Area of science
concerned with extraction of
information from numerical data and
with making inference about a
population from data that are
obtained from a sample.
Basic Definitions (cont.)
POPULATION: set representing all
measurements of interest to the
investigator.
PARAMETER: an unknown
population characteristic of interest
to the investigator.
Basic Definitions (cont.)
SAMPLE: subset of measurements
selected from the population of
interest.
STATISTIC: a sample characteristic of
interest to the investigator.
Some Frequently Used
Statistics and Parameters
SAMPLE
POPULATION
MEAN
y

VARIANCE
s2


STANDARD
DEVIATION
s



PROPORTION

Basic Definitions (cont.)
STATISTICAL INFERENCE :
making an "INFORMED GUESS" about
a parameter based on a statistic.
(This is the main objective of statistics.)
STATISTICAL INFERENCE
GATHER DATA
POPULATION
SAMPLE
MAKE INFERENCES
PARAMETERS
 , 
2

,  ,  , etc.
SAMPLE STATISTICS
y,
s , s, ˆ , etc.
2

Ex St 801
Statistical Methods
end
Introduction