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Definition
- Qualitative variables
- No special order |
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Definition
-categories have an order
- distance between categories unknown (ie Dem- Mod- Rep) |
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-Numerical values with known, meaningful distances
- (monetary values)
-(percentages) |
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| 3 Objectives of Statistics |
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Definition
Design-how to answer the research Q
Description - (what does the data mean)
Inference- (predictions, external validity) |
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Definition
| Inferring individual-level relationships from aggregate-level results. |
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Definition
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Definition
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| the degree to which an instrument consistently measures a concept |
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Definition
| the degree to which a measure is likely to produce a concept’s true value |
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| 4 steps of operationalization |
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Definition
1) Clarify the Concept
2) Operationalize the concept as something measurable and concrete
3) Gather Data
4) Construct Variables |
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Definition
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| A graph that displays the data by using vertical bars of various heights, where the heights represent the frequencies |
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Definition
The mean is sensitive to the influence of a few extreme observations
Also, a skewed distribution (with or without outliers) will pull the mean towards its long tail |
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Term
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Definition
The middle of the data (i.e. the 50th percentile)
Put the data in order, then choose the central data point
If n is even, take the mean of the middle two data points |
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Definition
The most frequently occurring value
The most likely outcome among your data values |
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Definition
| limits the influence of outliers and its value does not respond strongly to changes in a few observations (no matter how large) |
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Term
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Definition
The most common measure
The standard deviation is approximately equal to “how much the average observation differs from the mean”
When this number is big, we’d say the average observation tends to lie far from the mean the data are very spread out |
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Term
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Definition
About 68% of the data will fall within 1 standard deviation of the sample mean
About 95% will fall within 2 standard deviations
Nearly all data will fall within 3 standard deviations |
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Definition
| is a numerical measure of the likelihood that a specific event will occur. |
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Term
| 4 assumptions of standard normal distribution |
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Definition
1) The total area under the curve is 1.0.
2) The curve is symmetric about the mean.
3) The two tails of the curve extend indefinitely.
4) Empirical Rule (covered last class): appx 68%- 95% -99% of observations fall within 1, 2, and 3 standard deviations from the mean respectively |
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Term
| standard normal distribution |
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Definition
| The normal distribution with μ = 0 and σ = 1 |
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