Final Deck 3 Flashcards
Contrast descriptive/inferential statistics
- Descriptive statistics describe a single variable/distribution
- Inferential statistics make inferences about a population based on a sample (uses 2 variables and compare them to each other)
Mean, median and mode use which type of statistics (descriptive or inferential?)
Descriptive
Standard Deviation uses which type of statistics? (descriptive/inferential)
Descriptive
Correlation uses which type of statistics? (descriptive/inferential)?
Inferential
T-Test uses which type of statistics? (descriptive/inferential)
Inferential
Anova uses which type of statistics? (descriptive/inferential)
Inferential
How to use the mean and standard deviation of standard (deviation IQ) scores to determine normal limits.
On standardize tests, the SD is 15. So if the mean score is 100, the range of normal limits is between 85 and 115 (1 SD below/above the mean)
Define correlation
The way in which two variables are related to each other. Correlation considers strength and direction of the relationship
Strength (as part of correlation)
- The consistency of the pattern (how close the dots are to the line)
- *the closer the dots are to the line, the stronger the correlation.
- *if the dots are farther away from the line, the weaker the correlation
- r value closer to positive or negative 1 means a stronger correlation
- r value closer to 0.3 means a moderate correlation
- r value close to 0 means a weak or non-existent correlation
Direction (as part of correlation)
- Is r positive or negative?
- Positive r- both values are either increasing/decreasing
- negative r- one value is increasing, the other is decreasing (inverse relationship)
What are two disadvantages of a correlation test?
- Does not identify confounding variables
- Does not explain why the variables are related
- Affected by range of scores/outliers
- Not effective for curvilinear relationships
Describe a t-test
- a t test can compare 2 groups only on another variable. Ex: pre-test, give intervention, post test → you are comparing group of scores 1 vs group of scores 2 on another variable (ex: intervention)
Independent Sample T-Test
- A type of t-test where unrelated samples comparing the results
- Two different samples of participants test under different conditions → Ex: Comparing control/treatment groups
Related Sample T-test
- One sample tested under two separate conditions
- Comparing related groups → Ex: comparing pre-test and post test after the same dependent variable (intervention)
Describe ANOVA
- testing to see if there is a difference between more than 2 variables.
- Ex: pre test, intervention, post test, 6 months go by, follow up test.
What is the difference between a t-test and an anova?
T-Test looks at two variables only, Anova looks at 3 or more
What are non-parametric tests?
- A non-parametric test is capable of analyzing quantitative data that is ordinal or categorical, or does not conform to assumptions of normality, linearity, and homogeneity
(every parametric (ie t-test/anova) has a non-parametric equivalent)
Name 4 non-parametric tests
- Mann-Whitney U test
- Wilcoxon signed-ranks test
- Kruskal-Wallis ANOVA by ranks
- Friedman two-way ANOVA by ranks