Represented by ____
Usual number of levels ____
Are intermediate levels possible ____
Usual # of levels:
Intermediate levels possible?
Numerical: #s -- Many -- Yes
Cate:Words or code # -Few - No
- Nom: Different levels
- Ord: Dif lvl+ Order of lvl
- Int: Dif lvls + Order of lvls +Dist between lvls
- Dif lvls+Order of lvls+Dist between lvls+
- Dist from 0
DO numbers have to be used to represent different levels?
Does zero mean none?
Can levels be placed in logical order?
- Yes in Numerical No in Categorical
- Absolute Zero: Yes in Ratio & No in Interval
Logical order= Yes in Ordinal No in Nominal
How often do you exercise?
2=Once a week
3=Once a month
4= < once a month
- Levels not equally far apart (ordinal)
- How many times per month do you exercise?
- *lvls are spaced equally far apart (ratio)
How much do you exercise?
0 = None (mean GPA =2.50)
1=A little (mean GPA = 3.00)
2=A lot (mean GPA = 3.50)
Measurement scales: What is best DV?
- Interval or Ratio
- *Easier to get significant result
- *Statistical analysis is simpler
- *Keeps as much info as possible
----------> Loses Info
- Age in years -> Median Split -> Young or old
- ^RAtio ^Nominal
IV can be Numerical or Categorical
- If numerical, best if IV varies markedly
- If categorical, best if design is balanced
- *Same # of participants in each cell
- *Required for optimal statistical testing
Turning Numerical Variable into Categorical Variable
Is usually bad because it loses potentially valuable information.
OK if there is a large "gap" between levels
Turning a numerical variable into a categorical variable is OK if there are _____ categories
Puberty, Speeding, legally drunk, mentally retarded etc
Sir Isaac Newton
- Science is cumalative
- Study Promising Ideas
- Avoid Needless Duplication
What does literature review involve?
- Determining what is already known
- Research is obtaining new knowledge
Designing your study
- Suggest research ideas:
- Have debates to resolve or theories to test
- Correct limitations
- Implement Future research ideas
Designing your study:
Identify Important Variables:
* DVs that might be affected by your IVs
- * Variables that might affect your DV
- *Include in study as IV, or control if its confound.
*Learn about problems to watch for
- Quantitative Lit Review
- Combine data from multiple studies
Analyses of large sets of data collected by others
Learn how to measure DV:
- Methods for measuring memory
- Number & Types of items on memory tests
- Questionnaires for measuring DV
Helping with your IVs
Learn how to manipulate...
Learn how to measure ......
- Identify Important Levels
- Ex: critical periods, unstudied levels
- Learn how to manipulate True IVS
- Ex: Manipulate mood, word frequency
- Learn how to measure False IVS
- Ex: Personality type, attachment style
Studies to review
Same IV W/Same lvls + Same DV = Replication
SameIV w/same lvls + Different DV = < Useful
Different IV + DIfferent DV = Useless
When reviewing studies, Usually u want DV to math than for IV to match
Primary vs Secondary sources
- Primary Source:
- Author describes research he/she conducted
- "I found that"
- Secondary Source: The author describes research someone else conducted.
- "she found that"
Primary vs Secondary Sources:
Books are usually.....
Magazine articles are always....
Journal articles are usually.... But into is mostly.....
Books = Usually secondary
Literature reviews = Secondary
Magazines articles = Always Secondary
Journal Articles = Usually Primary but intro = mostly secondary
When to use secondary sources....
- To get "quick and dirty" overview of new area
- Locate useful primary sources.
Use interlibrary loan as needed
APA reference Formats
Give others due credit
Relates to plagiarism, professionalism, and accessing the literature.
Cite references in text body and list references in references section
What should be cited?
* Studies described in literature review
- * Theories, study designs, or other ideas suggested by others.
- * Definitions and other direct quotes
- -No direct quotes allowed in psyc 3000!
- *SOurces of materials (questionaires etc etc)
Can be part of text
Can be parenthesized at end of sentence
Stanislaw (2006) found that grades increased after students provided their instructors with chocolate.
Bribing instructors with chocolate is unethical (Potter, 2007).
More Citation Examples
It has been suggested that the hills are alive (Rogers & Hammerstein, 1966)
Rogers and Hammerstein (1966) suggested that the hills are alive.
BEn and Jerry's (1983) finding has been challenged (Baskin & Robbins, 2004; Dreyer, 1998; Haad & Daz, 1999)
Order Multiple studies within parentheses ALPHABETICALLY
Rearrange entire citations; don't rearrange authors within a citation.
(Dont change Haag & Daz to Daz & Haag)
Include page numbers when when citing ____ and when including ____ _____.
Books --- Direct Quotes
Popeye and Brutus (1973, p. 43) investigated the effects of spinach on aggression.
When to include (Author et. al.).
When to use et al.
- 1 or 2 authors: Never
- ex: Barnes and Noble (2001)
- 3 - 5 authors: ex:
- 1st citation: Barnes, Noble, and Walden (1999)
- All citations after Barnes et al. (1999)
- 6 or more authors: Always
- Use et al. even for first citation
Bonds, McGwire, and Sosa (2002) claim that baseball players are naturally muscular. ... No drug testing is needed (Bonds et al.).
Include year of publication in citation unless....
Cite article only once per paragraph unless...
- Unless article is already cited in that paragraph
- Several articles are cited in same paragraph
Avoid citations in Abstract unless....
Do not cite first name or initials of authors unless....
- Article is a rebuttal or replication
- Several first authors have the same last name
What should be listed and how?
- List all cited works, don't list uncited works
- List in alphabetical order, not citation order
- Dont reorder authors within a work.
Reference Elements for Articles, Books, and Web Pages:
- Author, Year, Article Title, Journal Title, Volume, Issue (rarely), Pages, doi or home page URL
Books: Authors, Year, Chapter
, Book Title, Pages, City, Publisher
- Web Pages:
- Authors, Full date, Web page title, URL
Include issue only if each issue.....
- Starts over on page one
- Most scientific journals dont
- Most magazines and newspapers do.
Ampersands and et al.
7 > authors
If 2-7 authors= list all authors and use an ampersand (&) before last author.
7 > authors = list six authors then add ellipses (...); no ampersand before last author
Know when to use which measures for average and variation depending on the type of data:
(nominal, ordinal,interval, ratio)
and its distribution (normal or skewed, unimodal or bimodal).
-Nominal always give mode
- Ordinal with many give median
- Ordinal with few give mode
- - Interval/ratio if skewed give median and
- IQR goes with it
Objective 9: Know which APA section in which to report descriptive stats on participant characteristics, as well as how to
report the typical ones (sex and age).
Methods section (participant subsection)
Objective 11: Know the difference between numerical and categorical data and which measurement scales are associated with each.
- Numerical = numbers
- - Categorical = Data separable into categories
- that are mutually exclusive, for example, age groups.
Objective 12: Know which measurement scales are best for a DV.
- - Preferred scale is interval/ratio
- - IV levels need to be far apart if
Objective 13: Know how to manipulate or determine the levels of a numerical IV and a categorical IV
- - IV can be numerical or categorical
- - If numerical, best if IV varies markedly
- - If categorical, best if design is balanced
- - Same number of participants in each cell
Objective 14: Know under which circumstances it is OK to turn a numerical variable into a categorical variable.
- - When there are natural levels or real
- world categories. Ex: mph is numerical but it could be looked at as speeding
- vs. not speeding
Objective 15: Be able to state a possible new
research question and operationalize your IV and DV if given the RQ, method section, and discussion section of an APA-style research article
- - New research question can be same
- questions but different limitations
Objective 16: Know the difference between primary and secondary sources and how to use each in your own research
- - Primary source = presenting your own
- research; your main sources, incl. those in your lit. review, should be primary
- - Secondary sources: could be lit reviews;
- usually when someone is talking about someone else’s research; magazines/books
- usually secondary
Objective 17: According to APA rules, know under what circumstances citations should be provided
- - Fact from someone else, someone’s
- theory, or the type of scale measurement device that was designed by someone
Objective 18: Know how to reference articles in APA-style. Given several listings in a Reference section, be able to identify violations of APA rules.
- - Do not cite first names or initials of
- authors unless several first authors have the same last name
- B. J., & Klown, K. T.(1999).Itchy and Scratchy and adolescent aggression: When chainsaws aren't funny. Sunday Night on Fox, 40, 800-830. doi:1032.2243/snf.1999.203
Extranious Variables: Ones that could have impact on DV.
Confounding Variables: Ones experimenter does not know but DO impact DV
Objective 4: The difference between descriptive and inferential statistics.
- descriptive: describes sample, there are
- inferential: inferences based on sample
about characteristics of population
1. sample size
2. average – mode is most frequent, mean is average, median is the middle number
Objective 6: Know how to calculate, by hand, the main measures of average (mode, median, mean) and
variation (SD, variance, range, IQR)
PRO AT THIS
Objective 1: Know the difference between a true and quasi IV.
- True IV: researcher sets (manipulates)
- - Quasi IV: researcher observes (doesn’t
- manipulate) ex: age, sex
Objective 2: Know the difference between an IV level and a cell or condition in an experiment with multiple IVs.
- - Ex: gender has 2 levels (male/female),
- academic has 4 levels. Cells/conditions of the two would be 8
- - There is a combination of levels when
- you have more than 1 IV