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16 Cards in this Set
- Front
- Back
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What is the five-number summary?
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Minimum, Q1, M (median), Q3, Maximum
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How do you calculate the first quartile?
The third? |
Q1: Find the median of the observations whose position in the ordered list is to the left of the location of the overall median.
Q3: Same as Q1, but to the right |
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1. How do you calculate the Interquartile Range (IQR)?
2. What is it? |
1. Q3-Q1
2. A measure of the spread of Data |
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What does 's' signify?
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The Standard Deviation of a sample
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What does s^2 signify?
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The variance
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What is the mean of a density curve?
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Its balance point
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What is the 68-95-99.7 rule?
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About 68% of the observations will fall within 1 SDEV of Mean Mu
About 95% will fall within 2 SDEV of Mean Mu About 99.7% will fall within 3 |
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How do you abbreviate Normal distribution?
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N(mean Mu, Standard Dev Sigma)
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How do you calculate a z-score?
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('x' - mu) / sigma
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How do you find percentile? (or unstandardize a z-score?)
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1. Use table A backwards to find z. For example, if you're looking for 90th percentile, look for the number in the body of the chart that is closest to .9, which is .8997. The z-score that corresponds to this is 1.28. 1.28= z
2. x= mu + z(sigma) |
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What are the three tests for assessing normality?
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1: Visual inspection of the distribution
2: Conformity to the 68-95-99.7 rule 3: Normal Quantile Plot |
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What are categorical variables?
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places each individual into a category, such as male or female
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What are quantitative variables?
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numerical values that measure some characteristic of each case, such as height in centimeters or annual salary in dollars
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How do you find conditional distribution?
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look at the value of one variable in relation to another variable
like, the percent of WOMEN who binge drink as opposed ALL people who binge drink |
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How do you find marginal distribution?
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row totals (or column totals) / total observations
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what is the difference between an observational study and an experiment?
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An experiment administers a new variable with subjects assigned to a random group, an observational study follow subjects and have more outside variables
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