Research Flashcards
Hawthorne effect
Change in behavior that occurs when individuals know they are being observed by researchers or others
Belmont effect or report (3 principles & 3 practices)
Report in ‘78/’79 as result of ethical violations in human subject/medical research:
3 core principles: respect for persons, beneficence, and justice
3 core practices: informed consent, assessment of risks and benefits, and selection of subjects
Convergent validity
Correlating one test to another similar existing measure
Concurrent validity
Correlating test to external measures (“here and now”)
Content validity vs criterion validity
Content = test items properly represent what they're meant to test Criterion = relationship btw test scores and another standard (concurrent or predictive)
Kuder-Richardson or coefficient alpha reliability
Statistical analysis of each item against all other items (all possible split half combinations). K-D for true/false and alpha for rating scales.
Z score
Z = x - m / sd
positively skewed curve–where are mean, median, mode?
positive skew=long tail positive;
mean highest,
median middle,
mode lowest
Internal validity
Study measures what it says it’s going to measure (extraneous variables don’t interfere)
External validity
Generalizability beyond the study
Reliability
Repeatability of results.
Type I (alpha) error
False rejection
Type II (beta) error
False acceptance
Validity vs reliability
If valid, must be reliable (repeatable). If reliable, does not necessarily mean valid.
T score
mean = 50, SD = 10
Rosenthal effect
higher expectations lead to increased performance
ANOVA
Compares the mean of k groups based on one independent variable.
-tests the significance of group differences between two or more groups
-the IV has two or more categories
-only determines that there is a difference between groups, but doesn’t tell which is
different
ex: Do SAT scores differ for low-, middle-, and high-income students?
chi-square
Determines if the observed frequencies are different from what we would expect to find.
ex: Is the distribution of sex and voting behavior due to chance or is there a difference between the sexes on voting behavior?
independent sample t-test
Compares the mean difference between two independent groups on a given variable
-the IV must have only two groups (male/female, undergrad/grad)
Do males and females differ in the amount of hours they spend shopping in a given
month?
ANCOVA
same as ANOVA, but adds control of one or more covariates that may influence the DV
ex: Do SAT scores differ for low-, middle-, and high-income students after controlling for
single/dual parenting?
MANOVA
same as ANOVA, but you can study two or more related DVs while controlling for the
correlation between the DV
-if the DVs are not correlated, then separate ANOVAs are appropriate
ex: Does ethnicity affect reading achievement, math achievement, and overall scholastic
achievement among 6 graders?
MANCOVA
same as MANOVA, but adds control of one or more covariates that may influence the
DV
ex: Does ethnicity affect reading achievement, math achievement, and overall scholastic
achievement among 6 graders after controlling for social class?
correlation coefficient
r
.55 strong correlation
.3-.55 moderate
coefficient of determination
r2
denotes the strength of the linear association between x and y
For example, if r = 0.922, then r 2 = 0.850, which means that 85% of the total variation in y can be explained by the linear relationship between x and y (as described by the regression equation). The other 15% of the total variation in y remains unexplained. The coefficient of determination is a measure of how well the regression line represents the data. If the regression line passes exactly through every point on the scatter plot, it would be able to explain all of the variation. The further the line is away from the points, the less it is able to explain.
