# PSY 210 Final Study Guide

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1. What is statistics?
Value that describes a sample
2. What is population?
Set of all inividuals of interest in a particular study
3. What is sample?
Set of individuals selected from a population, usually inteded to represent the population in a research study
4. What is parameter?
A value that describes a population
5. Independent variable vs. dependent variable
• Independent variable: the variable being manipulated by the researcher
• Dependent variable: the one that is observed to assesss the effect of the treatment
6. Symbolic notations
• Add all of the scores in the group.

• Compute inside parentheses first, then square it.

• Square each score, then add up squared scores.
7. Frequency distribution
8. histogram
9. bar graph
10. polygraph
11. Shape of Distribution
Positively skewed
12. Shape of Distribution
Negatively skewed
13. leptokurtic
14. platykurtic
15. Measures of Central Tendency: Mode
The score or category has the greatest frequency
16. Measures of Central Tendency: Median
The score that divides the distibution in half
17. Measures of Central Tendency: Mean
Arithmetic average
18. Which Measure of Central Tendency is most influenced by outliers?
• Mean
• Incorporate every score
19. Variance Equation
variance = mean squared deviation =

• sum of squared deviations
• number of scores

20. Sample Variance Equation
21. Population Standard Deviation
22. Sample Standard Deviation
23. Definitional Formula
24. Computational Formula
25. What causes variance to go up?
26. What causes variances to go down?
27. How to determine probability of z-score
Base probability percentage with z-score of normal distribution

• Example:
• Given:
• What percent scored higher than you on a test?
• P(z>+1.00)=.1587 (15.87%)
28. How to find a z-score with that probability
Example: For a normal distribution, what z-score separated the top 10% from the rest of the distribution?

• Z=+1.28
29. Standard error
• Standard distance between M and
• How well a sample mean estimates its population mean
• Smaller standard error, better estimation

30. Standard Error vs. Standard Deviation
31. t-Statistic

32. Independent t-test
• A research deisng that uses a separate group of participants for each treatment condition (or for each population)
• AKA between-subjects deisgn

• Estimated Error:
• Pooled Variance:
33. Dependent t-test

34. #38 on Test: On average, what value is expected for the F-ratio if your null hypothesis is true?
35. Correlation
A statistical technique that is used to measure and describe a relationship between two variables

NO manipulation of variables, just looking if 2 variable have a relationship to each other
36. Positive correlation
2 variables that you are comparing move in the same direction
37. Negative correlation
2 variables that you are comparing move in opposite directions
38. Parametric test
• Inferences about population from statistics that you calculated
• Test hypotheses about population parameters
• Require a numerical score for each individual
• Require data measured on an intercal or ratio scale
39. Nonparametric Tests
• Do not make statements about relationships to population parameters
• Data can be measured on nominal or ordinal scales
• Require fewer assumptions
• Are less sensitive than parametic tests
 Author: ralejo ID: 153746 Card Set: PSY 210 Final Study Guide Updated: 2012-05-14 21:20:40 Tags: statistics psy 210 csulb Folders: Description: statistics final psy 210 Show Answers: