Class Announcements

1
Class Announcements

• Test 2, Thursday, Dec. 5th from 2-4p.m.
• Locations are the same as Test 1
• Location Surname Range
• WW 111 A-God
• CG 150 Gom-Low
• CG 250 Lu-Shaw
• CG230 She-T
• OISE Aud V-Z
• T.A. Office Hours posted in Class Announcements
  on the Website

2
How Research Filters Perception
R E A L I T Y
Values, Theories, Existing Research, Methods
3
The Research Cycle
4
Measurement as Target Practice Validity,
Reliability, and Generalizability Compared
1.Not Valid, Not Reliable
2. Not Valid, Reliable 3. Valid,
Not Reliable
x x x x
x x x
x
x x x x
4. Valid, Reliable 5. Valid,
Reliable, Generalizable (Target 2)
xx xx
xx xx
Validity, reliability, and generalizability may
be explained by drawing an analogy between
measuring a variable and firing at a bulls-eye.
In case 1, above, shots (measures) are far apart
(not reliable) and far from the bulls-eye (not
valid). In case 2, shots are close to each other
(reliable) but far from the bulls-eye (not
valid). In case 3, shots are close to the
bulls-eye (valid) but far from each other (not
reliable). In case 4, shots are close to the
bulls-eye (valid) and close to each other
(reliable). In case 5, we use a second target.
Our shots are again close to each other
(reliable) and close to the bulls-eye (valid).
Because our measures were valid and reliable for
both the first and second targets in cases 4 and
5, we conclude our results are generalizable.
5
Designing an Experiment

• Selection of subjects
• Random assignment of subjects to experiment and
  control group
• Measurement of dependent variable in experiment
  and control group
• Introduction of independent variable to
  experiment group
• Remeasurement of dependent variable in
  experimental and control group
• Assessment of experimental effect

6
Design a survey on sexual harassment in the
workplace

• Who would you sample?
• How would you select the sample?
• What type of survey would be best (phone, mail,
  face-to-face)?
• What survey questions would you ask that measure
  sexual harassment?
• - Try to design three questions that you think
  are reliable and valid

7
Early Sexual Harassment Survey Items

• Have you ever been sexually harassed at work?
• Has anyone at work ever made sexual remarks to
  you?

8
Current Sexual Harassment Survey Items

• 1. In the past 24 months, has someone you worked
  with told dirty or sexually offensive stories or
  jokes?
• 2. In the past 24 months, has someone you worked
  with said offensive things about your body or sex
  life?
• 3. In the past 24 months, has someone you worked
  with made you uncomfortable by standing too
  close?

9
Turning a Classroom into a Contingency Table
BACK
more than 10 hours TV per week and no act of
physical violence per year
10 or fewer hours TV per week and no act of
physical violence per year
LEFT
RIGHT
10 or fewer hours TV per week and at least 1 act
of physical violence per year
more than 10 hours TV per week and at least 1 act
of physical violence per year
FRONT
10
TV Viewing By Aggressiveness
11
TV Viewing By Aggressiveness (men only)
12
Testing an Association for Spuriousness
(1) We believe there is a causal relationship
between TV viewing and aggressiveness TV
viewing Aggressiveness (independent
variable) (dependent variable) (2) By
controlling for gender we can see whether gender
has created a spurious association between TV
viewing and aggressiveness TV
viewing (independent variable) Respondents
gender (control variable) aggressiveness
(dependent variable)
(association)
(association)
(no association)
(association)
13

• Number of Sex Partners by Respondents Sex, USA,
  1996 (in )
• respondents sex male female
• number of sex partners
• 0 or 1 80 89
• more than 1 20 11
• total 100 100
• n 870 1008

14

• Number of Sex Partners by Respondents Sex, USA,
  1996, Married People Only (in )
• respondents sex male female
• number of sex partners
• 0 or 1 96 98
• more than 1 4 2
• total 100 100
• n 487 605