Class Notes
(807,463)

Canada
(492,743)

York University
(33,498)

Psychology
(4,069)

PSYC 2510
(86)

Agnieszka Kopinska
(18)

Lecture

# Introductory Statistics

Unlock Document

York University

Psychology

PSYC 2510

Agnieszka Kopinska

Fall

Description

INTRODUCTORY STATISTICS
Statistics – the use of numbers that allows for the collection,
classification, and interpretation of facts
Another way of quantifying properties of objects or events of interest
Increase precision of communication/description
Used to go beyond the numbers
Population – all members of a group who are alike on at least one
specified characteristic
Sample – any number of cases less than the total number of cases in the
population from which it is drawn
Usually the object of studies
Used to make inferences about the characteristics of the larger
population as a whole
Must be representative of the population to draw meaningful and
accurate inferences
Samples from different populations can be compared in a study
Must be comparable – members of both samples would be
expected to perform in the same way when tested in the same
conditions
Selection methods matter
TYPES OF SAMPLES
Radom Sample – each member of the pool has an equal probability of
being selected on any given draw and each possible sample of members
has an equal probability of being selected
May not be representative
Random from the whole population
Randomized sample – each member of the sample has an equal chance
of being assigned to a given condition of the experiment
Already have your sample, but they are assigned to different parts of
the study
Matched sample – yields pairs of observations to produce highly
comparable groups
Two participants paired based on similarities in relevant
characteristics and each takes part in one of the conditions
OR
The same participant takes part in both conditions
Most suitable for experiments in which there are only 2 groups
PARAMETERS AND STATISTICS
Population parameters – the properties of populations E.g. The average number of books read by college graduates last year
in North America
TYPES OF DATA
Numerical data – data in numbers
Tell us how much of a given property each sample member exhibits
Magnitude data – number indicating the amount of a property
that exists along a continuum (“how much”)
Rank-order (ordinal) data – amounts of a property expressed as a
rank relative to other individuals (1 , 2 , 3 )d
Categorical/Nominal Data – information that reflects mutually exclusive
categories in which participants fall
Either the characteristic is displayed or it isn’t
E.g. male or female, tall or short
TYPES OF STATISTICS
Descriptive statistics – used to organize and summarize data
Measures of central tendency – common patterns in data (the
mean, median and mode)
Normal distribution – mode, median and mean are all equally
distributed
Stability – the mean is usually the most stable across samp

More
Less
Related notes for PSYC 2510