PSYCH 100 - Chapter 2 part 2 Flashcards
control (or comparison) group
In an experiment, a group or condition in which some proposed cause is not present. (2.9)
placebo condition
In an experiment, a group or condition in which people expect to receive a treatment but are exposed only to an inert version, such as a sugar pill. (2.9)
random sampling
A way of choosing a sample of participants for a study in which participants are selected without bias, for example, by dialing random digits on the telephone or pulling names out of a hat. (2.1)
validity
The appropriateness or accuracy of a conclusion or decision. (2.13)
construct validity
The specific assessment of how accurately the operationalizations used in a study capture the variables of interest. (2.13)
reliability
The degree to which a measure yields consistent results each time it is administered. (2.13)
external validity
The degree to which it is reasonable to generalize from a study’s sample to its population of interest. (2.14)
internal validity
The ability of a study to rule out alternative explanations for a relationship between two variables; one of the criteria for supporting a causal claim. (2.15)
confound
An alternative explanation for a relationship between two variables; specifically, in an experiment, when two experimental groups accidentally differ on more than just the independent variable, which causes a problem for internal validity. (2.15)
descriptive statistics
A graph or computation that describes the characteristics of a batch of scores, such as its distribution, central tendency, or variability. (2.17)
frequency distribution
A descriptive statistic that takes the form of a bar graph in which the possible scores on a variable are listed on the x-axis and the total number of people who had each score is plotted on the y-axis. (2.17)
mean
A measure of central tendency that is the arithmetic average of a group of scores. (2.17)
median
A measure of central tendency that is the middlemost score; it is obtained by lining up the scores from smallest to largest and identifying the middle score. (2.17)
mode
A measure of central tendency that is the most common score in a batch of scores. (2.17)
variability
The extent to which the scores in a batch differ from each other. (2.17)
standard deviation
A variability statistic that calculates how much, on average, a batch of scores varies around its mean. (2.17)
effect size
A numerical estimate of the strength of the relationship between two variables. It can take the form of a correlation coefficient or, for an experiment, the difference between two group means divided by the standard deviations of the two groups. (2.18)
inferential statistics
A set of procedures used to estimate whether a pattern of results represents a true relationship or difference in the population. (2.19)
statistical significance
A process of inference that applies rules of logic and probability to estimate whether the results obtained in a study’s sample are the same in a larger population. (2.19)
meta-analysis
A process in which researchers locate all of the studies that have tested the same variables and mathematically average them to estimate the effect size of the entire body of studies. (2.19)
Institutional Review Board, IRB
A local panel of researchers, teachers, citizens, and others who determine whether a research study lives up to the community’s ethical standards. (2.20)
informed consent
An application of the ethical principle of autonomy, in which a researcher explains the procedures of a study, including its risks and potential benefits, to the potential participants, who then decide whether to take part. (2.20)
false positive
A statistically significant finding that does not reflect a real effect. (2.22)
HARKing (hypothesizing after the results are known)
A questionable research practice in which researchers create an after-the-fact hypothesis about an unexpected research result, making it appear as if they predicted it all along. (2.22)
