What are quartiles and percentiles how can we use these

Question

What are quartiles and percentiles? How can we use these concepts in the real world?

1. Briefly describe how the three quartiles are calculated for a data set. Illustrate by calculating the three quartiles for two examples, the first with an odd number of observations and the second with an even number of observations.
2. Explain how the interquartile range is calculated. Give one example.
3. Briefly describe how the percentiles are calculated for a data set.
4. Explain the concept of the percentile rank for an observation of a data set.

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