# Statistics Final

## Terms

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- What is the formula for a z score?
- z=(x-mean)/standard deviation
- What is the within group degrees of freedom for ANOVA?
- N-k
- What is the between group degrees of freedom for ANOVA?
- k-1
- What is the total degrees of freedom for ANOVA?
- N-1
- What is the degrees of freedom for Factor 1 of ANOVA?
- # of factor 1 levels-1
- What is the interaction degrees of freedom for ANOVA?
- The degrees of freedom for either factor
- Type I Error
- Erroneously reject the null hypothesis
- Type II Error
- Erroneously accept the null hypothesis
- What are the two main classes of statistics?
- Descriptive and inferential
- Variance=
- (score-mean)2/N-1
- Standard deviation=
- Square root of variance
- How do you find the empirical t value in a t-test?
- Use t=(sample mean-population mean)/[standard deviation/(square root of N)]
- When do you use a t-test?
- When you're trying to determing whether it's likely that a sample stemmed from a population with a given mean
- Decision rules for a t-test
- If the observed t is between the critical values, do not reject the null hypothesis. If the observed t value is outside of the critical values, reject the null hypothesis.
- What is the 95% confidence interval?
- mean (+/-) 1.96(standard deviation/square root of N)
- If there are 20 people: 10 females and 10 men, what is the degrees of freedom?
- 18
- How do you find the observed t value when you are trying to determine whether there are differences between two groups?
- mean1-mean2/long, complicated demonimator
- What is the 95% confidence interval using two groups?
- (mean1-mean2) (+/-) alpha t value(complicated denominator)
- When do you use a standard normal (z) distribution as opposed to the t-distribution?
- Use z when you know the population standard error. Use t when the error is estimated from the sample.
- What is the Pearson correlation coefficient symbolized by?
- r
- What is the degrees of freedom for Pearson's?
- N-2
- How do you determine a percent of variance?
- r squared
- What kind of correlation would you use to test the relationship between rankings?
- Spearman rank order correlation (r sub s)
- Regression is used to...
- ...predict one variable from another
- Correlation is used to...
- ...find the degree of linear relationship between two variables
- If the F ratio approximates 1, that means...
- ...there is no treatment effect
- How many variables and levels are there in a 2x2x4 factorial design?
- 3 variables, 2, 2, and 4 factors
- How do you determine the number of levels from the degrees of freedom?
- Add one
- How do you determine the number of groups from the degrees of freedom?
- (dfA+1)(dfB+1)
- How do you find the total amount of between group variability?
- SStotal-SSwithin