Arranging Comparisons
What is the null hypothesis in any research study?
Any observed differences are due to chance.
Define simple random sampling.
Everyone in the population has an equal likelihood of being selected.
Name an example of a nominal variable.
Gender, race/ethnicity, etc.
Explain the difference between external and internal validity.
Internal validity refers to the extent to which a set of research findings provide compelling information about causality.
External validity refers to the extent to which research findings provide an accurate description of what typically happens in the real world.
Define accuracy and precision.
Precision means the ability of a measurement to be reproduced consistently.
Accurate means the ability to get to the true or actual answer.
Identify the IV and DV:
How does phone use before bedtime affect sleep?
IV: Phone use
DV: Sleep
Define snowball sampling.
A non-probability sampling method where currently enrolled research participants help recruit future subjects for a study.
As part of a test preparation course, students are asked to take a practice version of the Graduate Record Examination (GRE). This is a standardized test. Scores can range from 200 to 800 with a population mean of 500 and a population standard deviation of 100. What scale of measurement does this represent?
Interval
You take your temperature with a thermometer three times over a 20-minute period and observe the following measurements: 98, 106, and 89 degrees. Describe the reliability of the thermometer.
The reliability of the thermometer is low.
Provide an example of a double-barreled question.
This year, Spring in Chicago was cold AND devastating.
A researcher finds that the more a song is played on the radio, the greater the liking for the song. However, she also finds that if the song is played too much, people start to dislike the song. What type of relationship does this represent?
Curvilinear
Your research methods instructor asks you to distribute a survey on cheating to a random sample of students. To save time, you go to the cafeteria and distribute the surveys among the students who are there. The sampling method is called ________ sampling.
Haphazard sampling
Name an example of a ratio measurement.
Height, weight, degrees Kelvin.
What problem(s) with experimental designs leads to low external validity?
Non-representative environment
Non-representative sample
Define falsifiable.
Can be disproven by experimental observation.
Three elements needed to determine causality.
A) Temporal precedence
B) Covariation of cause and effect
C) Elimination of alternative explanations
What sampling method is the best way to ensure the racial/ethnic composition of the population is represented in the sample?
Stratified random sampling.
What type of measurement is the mental health in our class study represented by?
Ordinal
A participant’s performance decreases throughout the experiment. The researcher notes that they appear to be frustrated. This is an example of…
Fatigue effects
How is a theory different from a hypothesis?
In scientific reasoning, a hypothesis is constructed before any applicable research has been done. A theory, on the other hand, is supported by evidence: it's a principle formed as an attempt to explain things that have already been substantiated by data.
Name two advantages and two disadvantages of mailing a survey to participants.
ADVANTAGES: Less expansive, larger population available, reduced interviewer bias
DISADVANTAGES: lower response rate, response bias (who fills out), researcher not present to assist with problems
Explain the difference between systematic and random error.
Random error is error that occurs naturally and can be higher and lower than the desired measurement, while systematic error consistently yields results either higher or lower than the correct measurement.
How does an interval measure differ from an ordinal measure?
The distance between attributes has meaning.
Name three threats to internal validity.
Pretest sensitization
Instrumentation effects
Demand characteristics
Confounding variables
Use necessary and sufficient in a sentence describing how frustration relates to aggression.
If frustration is necessary for aggression, someone who is aggressive but always be frustrated. If frustration is sufficient for aggression, frustration must always lead to aggression.