3001 2-1 Flashcards
(22 cards)
Measures of Central Tendency
mean, median, mode
Measures of Variability
variance, standard deviation
Linear regression
finding the best-fitting line
Regression Coefficients
slope and intercept
Y = a + bX
b = slope
a = intercept
positive slope =
positive or -> relationship
negative slope =
Negative or <- relationship
Pearson product-moment correlation
coefficient
r
-1 less than or equal to r less than or equal to 1
2 pieces of information we can get from r
- The sign of r tells us whether there is a positive or negative relationship.
- r-squared tells us the proportion of variance in Y that is attributable to X (strength of the relationship).
When r does not equal +/- 1
- only a portion of the variability in one variable is related to variability in the other
- predictions of one variable from the other will be imperfect
- other factors influence the two variables (e.g. error variance)
r is _____, p (rho) is _____
a sample statistic
the corresponding population parameter
Spurious relationship:
When two variables are correlated but not causally related (they are related by coincidence or chance)
How can we tell if a correlation is meaningful or just a coincidence?
Ideally, there would be a theory supporting the existence of a relationship between the variables
measurement
Assigning numbers or labels to observations to represent amounts or categories
Measurement Scale
Set of possible numbers or labels that can be assigned to measured items
Properties of Measurement Scale
magnitude
equal unit size
absolute zero
magnitude
Measurements can be arranged in order
Equal unit size
a change of 1 is the same size across
the scale
Absolute Zero
a score of 0 means there is none of
what is being measured
4 categories of measurement scales
ratio, interval, ordinal, nominal
Interrater reliability/agreement:
extent to which the observations of different observers agree
coding system
a method for categorizing and analyzing qualitative or behavioral data in psychology. It involves assigning labels (codes) to observed behaviors, verbal responses, or text to identify patterns and facilitate analysis.
