Lecture 4 Flashcards
What is the term for something that produces stable and precise measurements?
Reliability
If we get the same results over and over again the results are?
Reliable
How is reliability assessed?
Test-retest
parallel/alternate forms
Internal-consistency (cronbach’s alpha)
What are the essential characteristics of a good measurement?
Reliability
Validity
What is the term for when the instrument measures what it’s supposed to?
Validity
What is test-retest reliability?
Reliability across time
Parallel/alternate forms is reliability?
Across different versions of a test/questionnaire
Internal-consistency reliability measures what?
Stability within the measurement instrument
In psychology we want our measures to have what reliability scores?
> /= .80 (strongly correlated)
If a measure is not reliable it can be what?
Valid
What are the 3 ways validity is assessed?
content validity
criterion-related validity
construct validity
What measure includes all relevant content for the construct is’t supposed to measure?
Content Validity
What looks like it’s measuring what it’s supposed to measure?
Face validity
What measure coincides with present performance or predicts future performance?
Criterion-related validity
What type of validity describes scores on a test being similar with other measures of the construct?
Concurrent validity
What type of validity accurately predicts future performance related to construct?
Predictive
What measure captures the theoretical construct is was designed to measure?
Construct Validity
Construct validity is established by demonstrating what two subtypes of validity over time?
Convergent
Divergent
What measure correlates with other measures related to the same construct?
Convergent validity
Whta measure doesn’t correlate with other measures that are not related to the construct?
Divergent (Discriminant) Validity
What does validity require?
Reliability
You can have a measure with what?
Low reliability
High validity
What are the purposes for doing correlational research?
examined relationships between naturally occurring variables.
What is the purpose of a scatterplot?
describe strength and direction of relationship between variables
strength on scatterplot is indicated by what?
how close the points cluster together
direction on scatterplot is indicated by what?
whether the ling slopes up or down from L to R.
What are the types of relationships between variables as shown by scatterplots?
Positive
Negative
No relation
Curvilinear
As one variable increases the other also tends to increase or as one decreases the other also decreases. This is know as what type of relationship?
Positive
As one variable increases the other tends to decrease or as one variable decreases the other increases. This is known as what type of relationship?
Negative
When variables don’t have a linear relationship with each other what type of relationship is that?
No relationship
What type of relationship is described as one variable increasing while the other variable increases and decreases?
Curvilinear
What is the most common mathematical way of summarizing the strength and direction of linear relationship between 2 continuous variables?
Pearson product-moment correlation coefficient: Pearson’s r (correlation coefficient)
When a correlation coefficient is close to 1.00 what type of relationship is that?
Stronger
When a correlation coefficient is close to 0.00 what type of relationship is that?
Weak
Correlation coefficients can only be used for what type of relaitonships
Linear
What is the null hypothesis?
Ho-no relationship or not expected relationship will be found
What is alternate hypothesis?
H1-expected relationship will be found
When doing a non-directional two tailed hypotheses what would you say
There is a relationship between X and Y.
directional one tailed hypotheses are based on research hypotheses of what?
Positive OR negative but not both
What does a P value tell you?
The probability that you got the correlation due to chance if null was true/
Example of p value results?
P value of .32 means 32% of the time you could find a relationship if null is true.
What is the amount of chance you are willing to accept?
Alpha level
If p value is less than alpha what does that mean?
Reject Null
If p value is more than alpha what does that mean?
Fail to reject null
What allows you to interpret the relationship in terms of variance explained?
Effect size
The effect size is called what?
Coefficient of determination or r2
r2 tells you what?
Proportion of variance in one variable that can be predicted by the other.
How to report correlation in APA?
r(N)=PearsonsR, p>,05/.01, r2=.**
r2 equals what?
Square of Pearson’s r/correlation coefficient
After you know 2 variables are correlated you can use on to predict the other; this is called?
Linear regression analysis
