Anything that can have more than one
ie. Height, weight, sex, IQ, video games
Anything that remains the same
ie. Study on females (females remains
Utilizes the organization of raw data that has
already been collected
Expressed in different ways:
1. Histogram (Bar graph)
x axis (abscissa) - horizontal
y axis (ordinate) - vertical
2. Pie Chart
3. Polygon (Line graph)
Which class performed better?
Class A Class B
% on test % on test
Ss 1 Ss2 Ss3 Ss4 Ss1 Ss2 Ss3 Ss4
numbers are used to name or categorize
(ie. Sports uniforms, gender,driver’s licence)
numbers represent serial position
(ie. Finish in a race, rankings, level of
Measurement Scales cont.
consistent units if measurement and equal
spacing between units (no true zero point)
Same as interval, but has absolute zero point
ie. Weight, height, time, distance
Types of Statistics
- A statistic to describe behaviour
- ie. SAT scores
- A statistic that explains behaviour
- Bandura’s Bobo doll experiment on aggression
- example: t-test or ANOVA (analysis of variance)
Measures of Central Tendencies
A single score that represents a whole
set of scores
Mode: Most frequently occurring score
Median: Middle score (half above and below)
Mean: Arithmetic average (most widely used)
When the data is not distributed evenly,
atypical scores can mislead the data
Always be aware of the measure of central
tendency that people are reporting
What is the Mode?
$41,000 What is the Median?
What is the Mean?
Normal Curve (Bell Curve)
Theoretical or hypothetical frequency of
68% between 1 and -1 SD
95% between 2 and -2 SD
99% between 3 and -3 SD
Examples: height, weight, IQ
The amount of variability between scores tells us the reliability
of the data
The lower the variability the more reliable the results
Basketball player example
Range: The gap between the lowest and the highest score
Crude estimate of variability based on extreme scores
- Standard measurement of how the scores in a
distribution deviate from the mean
- Better way to assess level of variability between
- Represented by lower case s
- ie. UBC vs. Kwantlen entrance marks
who has the smaller SD?
When is an observed difference
1. Representative vs. Biased Sample
Is it random and large enough?
2. Less variable observations are more
3. More cases are better
ie. Assessing which school is better?
- Statistical statement of how likely it is that an
obtained result occurred by chance
- “beyond a reasonable doubt”
- indicates the likelihood the result will happen by
- Does not indicate IMPORTANCE of result
- ie. IQ between first born and second born
Reliability & Validitiy
Reliability is the extent to which an
experiment, test, or any measuring
procedure yields the same result on
Validity refers to the degree to which a
study accurately reflects or assesses the
specific concept that the researcher is
attempting to measure.
Reliability & Validity
While reliability is concerned with the
accuracy of the actual measuring
instrument or procedure, validity is
concerned with the study's success at
measuring what the researchers set out to
Reliability & Validity
Measures relationship between two
- data must be interval or ratio
Pearson Product-Moment Correlation is
represented by small case r
If anything is paid attention to in our schools,
colleges, and universities, thinking must be it.
Unfortunately, thinking can be lazy. It can be
sloppy….It can be fooled, misled, bullied...
Students possess great untrained and untapped
capacities for logical thinking, critical analysis,
and inquiry, but these are capacities that are not
spontaneous: They grow of wide instruction,
experience, encouragement, correction, and
The Nestle Inc. authoritatively states that
Smarties are 25% pink, 20% green, 15%
brown,15% yellow, 15% orange, and 10%
purple. This distribution is important for
Is this true? Are they that accurate?
Three random boxes of mini Smarties. All boxes
are still originally sealed and have not been
Design a data sheet and complete your data
collection. (Ensure that you complete your data
before premature subject mortality occurs!)
Convert raw data into percentages
Develop a hypothesis based on the
distribution of the data you collected
Proving your hypothesis
Join up with two other classmates and
integrate your data.
Is your hypothesis still right?
Do you have a new hypothesis?