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Quintiles
Quintiles
Quintiles are a measure of quantile that divides a set of data into five equal parts, called quintiles.
Formula for Quintile:
Quintile = (n/5)th percentile
where:
- n is the number of the observation
- 5 is the number of quintiles
Calculating Quintiles:
- Arrange the data in ascending order.
- Calculate the number of observations (n).
- Multiply n by 0.20, 0.40, 0.60, 0.80, and 1.00 to find the quintile values.
- The values at these quantiles are the quintiles.
Interpretation:
- The first quintile (20th percentile) divides the data into the lowest 20% of values.
- The second quintile (40th percentile) divides the data into the lowest 40% of values.
- The third quintile (median) divides the data into the lowest 50% of values.
- The fourth quintile (60th percentile) divides the data into the lowest 60% of values.
- The fifth quintile (80th percentile) divides the data into the lowest 80% of values.
Example:
“`Data: 10, 12, 14, 16, 18, 20, 22, 24, 26, 28
n = 10Quintiles:First quintile = 10Second quintile = 14Median = 18Fourth quintile = 22Fifth quintile = 26“`
Advantages:
- Easy to calculate.
- Provides a good overview of the distribution of data.
- Can be used to compare groups of data.
Disadvantages:
- Can be misleading for skewed distributions.
- May not be suitable for small datasets.