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9 Cards in this Set
- Front
- Back
Define: Central Tendency. What are the three types? |
The extent to which the values of a numerical variable group around a central value. Mean, median, mode |
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Which measure of central tendency is affected by extreme values (outliers)? Why? |
Mean because it considers all the values, including outliers, in a data set equally. |
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What does variation measure? What are 4 examples of measures of variation? |
The spread or dispersion of the values in a set. 1. Range 2. Variance 3. Standard Deviation 4. Interquartile Range |
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How do variance and standard deviation aid in statistics? |
It helps define how the values are distributed. |
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In what situations are mean, median or mode useful? |
Mean is a useful average for data sets without outliers. Median is useful for determining the average in a set with outliers. Mode is useful for qualitative data sets (categorical). |
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Define: skewness |
The extent to which the values in a data set are not symmetrical from the mean. |
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How are quartiles calculated? How does one know the position? |
[ k(n+1)]/4, where k is the i-th position of the quartile. Position: 1. Whole number 2. Half 3. Rounded irrational numbers |
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Define: resistant measures. Give examples |
Descriptive statistics which are not affected by outliers. 1. Median 2. Mode 3. Quartiles |
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How is skewness determined? |
Mean - Median. If > 0, then it is positively (right skewed), or the tail is on the right side. If < 0, then it is negatively (left skewed), or the tail is on the left side. |