# psyc312-9

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1. To calculate z-score 2. Fromale for z-score to data value
X = µ + (zσ)
3. 3 types of probability
• subjective (personal judgement)
• Analytic/Theoretical - study all possible outcomes
• Expected relative frequency (Empirical) - on the long run, average
• given mutually exclusive events, sum the probabilities
• keyword: OR
5. Multiplication Rule
• for joint probabilities
• keyword: AND
6. Chi Square Goodness of Fit
• Used to test frequency distributions for ONE dimension
• Ei= npi || df = (k-1)
• 7. Chi Square: Contingency
• Er,c = (sum of Row) x (sum of column)
• sample size

df = (r-1)(c-1)
8. When do we reject the null?
x2(observed) > x2(critical), reject the null
9. Sampling Error
Random variability btwn observations or statistics due to chance
10. Sampling distribution
The distribution of a statistic over repeated sampling from a specified population
11. properties of Sample Means
• the mean of the sample is equal to the population mean (no calculation)
• the standard deviation of the sample is (standard error of the mean)
• 12. Variance formula 13. The Null Hypothesis
• The hypothesis that the manipulation had no effect.
• always contains = or ≤ or ≥
14. The alternative hypothesis
always contains ≠, < or >
15. The critical values
• represent the point at which we reject the null
• we reject the null when we exceed the critical value
16. 2 types of hypothesis tests
One tailed: one direction for rejection; left or right tailed

2 tailed: rejects null when value is too extreme in either direction; non directional
17. Decision based on a p-value
If p ≤ α (in critical region), reject the null

If p ≥ α (not in critical region), fail to reject the null
18. Types of errors
Type I error occurs if the null hypothesis is rejected but it's actually true (most serious)

Type II error occurs when the null hypothesis is not rejected but it's actually false
 Author: ctryhurn ID: 25317 Card Set: psyc312-9 Updated: 2010-06-30 14:22:43 Tags: psyc Folders: Description: psyc Show Answers: