Exam 2 Flashcards
sampling error
measurement =/ reality ex: variable (scale) – 1,3,4,5 i. Statistic (sample) – average = 3.75 ii. Parameter (population) – average = 3.72
i. Thus as sample size increases…
1. Sampling error decreases
2. Also, statistical power increases
ii. You need to get the sampling error down to a reasonable number
Perfect Probability Sample
a. The bar charts are exactly the same sample vs. population
Less-than-perfect probability
a. The bar charts differ sample vs. population
Normal curve
(normal distribution/bell curve) U shape symbol = mean/average
Nonprobability Sampling
i. Available subjects (convenience, generalization)
ii. Purposive sampling (judgment of usefulness and representativeness)
iii. Snowball sampling (person to person to…)
1. Sample is getting bigger as it passes from person to person and as we progress
iv. Quota sampling (pre-specified characteristics to match population)
1. Pick a specific number of samples to match “quota”
Types of sampling designs
a. Simple Random Sampling (random numbers 1-100)
b. Systemic sampling (kth numbers 1-100)
c. Stratified sampling (random selection from homogeneous strata)
d. Cluster sampling (random sample of clusters and then random selection from clusters)
Thomas E. Dewey
a. Born in Owosso, Michigan
b. University of Michigan and the Columbia university law school
c. Federal prosecutor and then governor of New York
d. Republican candidate in the 1948 presidential election
e. Gallup polls
i. Polling ended in early October
ii. Undecided voters went Truman
iii. Reliance on quota sampling (following WWII: population movement to cities
Probability Sampling
a. Population (aggregate of elements)
b. Sample
c. Sampling bias (sample =/= population)
i. Ex: 2 men having to represent 50 men.
d. Random selection (equal chance of selection)
e. Representativeness
f. Sampling error (degree of error in sample design)
g. Statistic (descriptive summary of a variable)
h. Sampling frame (a list of units that compose a population from which a sample is selected)
i. Weighting
Confidence level
– the estimated probability that a population parameter lies within a given confidence interval
i. Tells us how sure we can be
ii. Normally 95% confidence interval
Hawthorne Effect
a. People approve upon something simply as a result of their being studied.
b. Hawthorne Works commissioned an evaluation of how its workers would respond to having lower-to-higher levels of lights
c. Worker productivity improved during the study, but slumped afterward. (People didn’t want to lose their jobs when they were being watched)
List of appropriate topics for Survey Research
a. Units of analysis = respondents
b. Large samples, original data, measuring attitudes and orientations
c. Questionnaires:
i. Open-ended (broad; Asking without getting certain responses – “What did you do last night)
ii. Closed-ended (yes or no; choose from a list of answers – “What’s your age?)
d. Make items clear/relevant.
e. Avoid double-barreled questions (and/or)
i. Ex: “do you like Texas A&M or liver? Yes or no?
ii. Instead of asking two different things at the same time, ask two questions
f. Avoid negative items (NOT)
g. Avoid biased items and terms (welfare)
h. Avoid leading questions (like most Americans, don’t you think…)
Filter questions on survey questionnaires
i. “Have you ever smoked a cigarette in your life?”
1. The people who haven’t don’t answer anymore questions about it.
2. People who have get asked, “Have you smoked it in the last year? Have you smoked in the last month? How many do you consume each day?
3. This saves time and energy for those taking the survey…
Contingency Questions in Survey questionnaires
i. Questions that you answer in accordance with the first answer.
1. “Do you go to Texas A&M?” – “yes”
a. “Where do you live: on-campus or off-campus?”
Self-administered survey
- Open-ended vs. close-ended questions
- Mutually exclusive and exhaustive response choices
- Don’t know/no response/no opinion/undecided
- Primary vs. secondary
- Response rate: Ideal = higher than 70%
Primary vs. secondary data
a. Primary: the researcher has selected it themselves
b. Secondary: readily available and researched by another researcher
i. Sometimes it doesn’t have the proper question we want to use.
response rate: Mail distribution and return
why do people not return questionnaires?
- People perceive that they don’t have enough time
- We are constantly being sent surveys and we get overwhelmed, and therefore don’t respond.
Telephone (landline, cell) survey
advantages vs. disadvantages
- Advantages
a. Almost all households have a telephone
b. Time and money - Disadvantages
a. Unlisted phone numbers
b. Cell phones - Random-digit dialing (RDD)
- Computer-assisted telephone interviewing (CATI)
- There is more pressure for the interviewee to answer and not ignore
online survey
- Survey Monkey, Qualtrics, Survey Sampling Intl.
a. Search links, banner ads, email, online invitations, and co-registration
b. Digital fingerprinting implemented to authenticate respondents. - Low levels of interviewer and response biases
a. Impersonal; you don’t feel pressured to respond
Pretesting
i. Talking or writing on the level of your audience (children or people w/out an education) – comprehension level
f. Interview
advantages of Self-administered Questionnaires
i. Cheaper and faster than face-to-face interviews
ii. National is the same cost as local mailings
iii. Requires small staff
iv. More willingness to answer controversial items
advantages of interview surveys
i. Fewer incomplete questionnaires
ii. More effective for complicated questionnaires
iii. Face-to-face is more intimate
advantage of telephone surveys
i. Cheaper and more time efficient
Strengths and weakness of survey research
a. Strengths
i. Useful in describing large populations
ii. Surveys are flexible
iii. Standardized questions (same set of questions for each individual)
b. Weaknesses
i. Round pegs in square holes
ii. Seldom deal with context of social life
iii. Inflexible
iv. Artificial
v. Weak on validity (high in reliability)
Kansas Health Foundation
i. Purpose to improve health of children in state
ii. Tried to encourage adults to improve their social relationships with children
iii. Track and trend survey approach
Types of Evaluation Research Design
a. Experimental designs
b. Quasi-experimental designs – nonrigorous inquiries somewhat resembling controlled experiments but lacking key elements such as pre- and post-testing and/or control groups
c. Randomized controlled trails
i. Treatment
ii. Placebo
iii. Blind versus double-blind
d. Qualitative evaluations
Social indicators
measurements that reflect the quality or nature of social life. Social indicators are often monitored to determine the nature of social change in society.
i. Decrease people in the poverty line
Sampling frame
a list of units that compose a population from which a sample is selected
Experiments
i. Pros
1. Isolation of experimental variable’s impact over time
2. Replication
ii. Cons
1. Not representative
2. Artificiality of laboratory settings
Equal groups in experimental designs
a. Probability sampling rare in experimental designs
b. Instead use logic of random assignment when assigning subjects to groups
c. (Self-selection) preference must be random
d. Randomization: techniques for assigning experimental subjects
e. Matching: pairs of subjects matched on basis of their similarities on one or more variables.
One study by Albert Bandura et al
a. Goal: to study patterns of behavior associated with aggression
b. Social learning theory: aggressive behavior is learned through observing and imitating others
Terms in all types of experimental designs
a. IV → the cause
i. Part of experiment that can be controlled or changed
ii. Stimulus/intervention
b. DV → the effect
i. What is the main “measure” of the study?
c. By manipulating an independent variable (the cause), the researcher determines whether it influences the dependent variable (the effect).
d. Pre-testing & post-testing
Experiments involve:
a. Taking action
b. Observing consequences of that action