These lecture slides contain introductory material, along with information pertaining to measurement and notation.

1. Psychology 259:
Week 1
Introduction to Statistics
NOTE: You can skip information pertaining to:
5) Real limits (pg.21)

2. What is the purpose of statistics?
 Organize/summarize information
(Descriptive Statistics)
 Infer information about larger group
(Inferential Statistics)

3. Population
 entire group of individuals of interest to
researcher
 Parameter: value describing population

4. Sample
 subset of individuals representing
population
 Statistic: value describing sample

5. Sampling error
 Amount of error that exists between
sample statistic and corresponding
population parameter.

6. Important terms:
 DATA: information about group of
individuals
 VARIABLES: characteristic of individual
 CONSTANT: same characteristic for
every individual

7. Who? What? Why?
 WHO are our individuals?
 WHAT are we measuring?
 WHY are we measuring these
variables? (hypothesis?)

8. Study Design:
Correlational Method
 two variables observed for relationships
 less control
 no cause/effect concluded

9. Study Design:
Experimental Method
 More control
 Random assignment of individuals
 Experimental condition
 Control condition
 placebo

10. Independent and Dependent
Variables
 Independent Variable:
 Manipulated by researcher
 Dependent Variable:
 Observed variable
 outcome

11. Types of Variables
 Discrete Variables:
 separate categories
 Continuous Variables:
 infinite number of possible values falling
between two values

12. Scales of Measurement
 Nominal: categories
 Ordinal: relative rankings
 Interval: ordered categories with intervals of
same width
 Ratio: interval scale with absolute zero
point

13. Statistical Notation
X = score for a variable
Y = score for another variable
N = number of scores in population
n = number of scores in sample
Σ = summation
ΣX = summation of X values or sum of the scores