54 — Stats: understanding data

Averages hide what one number cannot tell you. This guide loads a list of numbers and reports several statistics, each answering a different question about the data.

#Steps

1. Create numbers.json with a list of scores:

   [5, 2, 9, 1, 7, 3, 5, 8]
   

   copyrun it →

2. statistics provides the library versions; the guide also computes the mean by hand so you can see what it means:

   from statistics import mean, median, mode
   

   copyrun it →

   sum(numbers) / len(numbers) is the mean: total divided by count. When the scores are ordered, the middle one is the median; the value that appears most often is the mode.

3. The full program loads the list and prints every statistic. Save stats.nme:

   # stats.nme — several statistics about one list.
   # Run: nme r stats
   # The file numbers.json must exist in the same folder.
   
   use file latest
   
   from statistics import mean, median, mode
   
   numbers = json_load("numbers.json")
   
   show f"count: {len(numbers)}"
   show f"total: {sum(numbers)}"
   show f"mean by hand: {sum(numbers) / len(numbers)}"
   show f"mean from statistics: {mean(numbers)}"
   show f"median: {median(numbers)}"
   show f"mode: {mode(numbers)}"
   show f"min: {min(numbers)}"
   show f"max: {max(numbers)}"
   show f"range: {max(numbers) - min(numbers)}"
   

   copyrun it →

4. Run it:

   nme r stats
   

   copy

   count: 8
   total: 40
   mean by hand: 5.0
   mean from statistics: 5.0
   median: 5.0
   mode: 5
   min: 1
   max: 9
   range: 8
   

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5. What each one tells you:

   • count — how many numbers there are.
   • mean — the balance point: if everyone got the total and split it evenly, each would get this.
   • median — the middle value when sorted; one unusually large or small score moves the mean but not the median.
   • mode — the most common value; the only statistic that works on categories, not just numbers.
   • min/max — the extremes.
   • range — how spread out the data is (max − min).

#Try it yourself

Replace numbers.json with [10, 9, 9, 8] and run again: the median stays 9 while the mean changes, showing why both matter.

#What you learned

• statistics.mean/median/mode summarize a list in one number each.
• sum(...) / len(...) is the mean by hand.
• min/max find the extremes; range = max − min.
• Mean, median, and mode answer different questions about the same data.