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20 Cards in this Set
- Front
- Back
mu =
x bar = s = s^2 = |
population average
sample average sample standard deviation sample variance |
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skew:
which direction is a positive skew? |
departure from symmetry
a positive skew is to the left |
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leptokurtic:
platykurtic: |
leptokurtic distribution has lots of tail
platykurtic distribution has lots of shoulder |
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central tendency:
extremes have greatest effect on what statistic? |
best description of middle of distribution (mean, median, mode)
extremes affect the mean the most because median/mode are only concerned with number of values and not actual values |
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central limit theorem
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Given a population with a finite mean (mu) and a finite variance (sigma^2), the sampling distribution of the mean will approach the normal distribution, with mean mu and variance (sigma^2/N), as N, the sample size, increases.
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given a population with the mean, mu, and a finite variance (sigma^2), ........
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the sampling distribution of the mean will approach the normal distribution with mean m and variance sigma^2/N as N, the sample size, increases
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DF for confidence interval:
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N-1
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DF for chi2 goodness of fit:
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g-1
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DF for chi2 test for independence:
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(rows-1)(columns-1)
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value for power in ANOVA:
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n-1
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chi2 goodness of fit is testing to see what? chi2 test for independence?
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goodness of fit: if events occurred by chance
independence: if 2 things are related |
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how many dimensions in chi2 gf test? chi2 independence test?
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gf: 1 dimension with unlimited categories
independence: 2 dimensions with unlimited categories |
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what type of error is it when the Ho is true, but you reject it?
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type one error; probability of occurring is alpha, 5%
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what type of error is it when the Ho is false, but you accept it?
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type two error; probability of occurring is beta,
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what does beta stand for?
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POWER! (the capacity for a type one or two error to occur)
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DF for critical f in ANOVA:
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numerator: g-1
denominator: N-g |
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assumptions of ANOVA:
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1. normality (populations from which data is drawn are normally distributed)
2. homogeneity of variance (error variance in populations of each group are approx equal) 3. independent errors (scores are independent so errors are unrelated) |
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power:
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capacity of a test to reject a false null.
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phi prime:
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measurement of effect size of experiment
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determinants of power:
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1. sample size
2. error variance (scores all over, but treated the same) 3. effect size (decaf coffee vs regular or decaf coffee vs poop) 4. alpha (larger alpha has more power) |