3.17 Intro to Data Science: Measures of Central Tendency—Mean, Median and Mode

  • Measures of central tendency:
    • mean—the average value in a set of values.
    • median—the middle value when all the values are arranged in sorted order.
    • mode—the most frequently occurring value.
  • Each represents a “central” value in a set of values.
    • A value which is in some sense typical of the others.
In [1]:
grades = [85, 93, 45, 89, 85]
In [2]:
sum(grades) / len(grades)
Out[2]:
79.4
  • sum and len are both examples of functional-style programming reductions
  • The Python Standard Library’s statistics module provides functions for calculating the reductions mean, median and mode.
In [3]:
import statistics
In [4]:
statistics.mean(grades)
Out[4]:
79.4
In [5]:
statistics.median(grades)
Out[5]:
85
In [6]:
statistics.mode(grades)
Out[6]:
85
  • Sorting grades helps you see the median and mode.
In [7]:
sorted(grades)
Out[7]:
[45, 85, 85, 89, 93]

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