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22 Cards in this Set
- Front
- Back
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Types of studies |
Expermental, Observational |
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Large set of data |
Population |
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Smaller Representation of data |
Sample |
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variability |
error |
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Best sampling technique |
Simple Random Sample(SRS) |
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Types of Variables |
Categorical/ Quanitative |
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Types of studies |
Enumerative-Well defined(study of our class) Analytical- Abstract population doesn't exist at once(cars on a street between a few hours)
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Steps of Stats |
Step 1:Collect Info Step 2:Summirize Info step 3:Draw conclusions |
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For skewed data whats the best mesurement |
Median |
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Variance and standard deviation are |
Strongly affected by outliers |
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Standerd devation |
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If we multiply all of the numbers in the data set by a non-zero constant c, the effect is to |
multiply the variance by the square of c multiply the standard deviation by c |
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Roughly of the data fall within one standard deviation of the mean |
68% |
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Roughly of the data fall within two standard deviations of the mean |
95% |
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Roughly of the data fall within three standard deviations of the mean |
99.7 % |
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IQR contains |
50% of the observations |
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not as sensitive to shape of distribution or to extreme values |
IQR |
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IQR works in that cases |
All cases, regardless of shape |
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Measures of Centrality |
Mean/ Median / Mode |
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Measures of Variablity |
Variance(Std dev), Range, IQR |
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For symmetric distributions |
mean = median = mode |
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For positively skewed distributions |
mean > median |
