text: const stat = require("./ch10-node-export");
  
  console.log(stat);
  
  let mea = stat.mean([1, 3, 5, 7, 9]); // => 5
  let std = stat.stddev([1, 3, 5, 7, 9]); // => Math.sqrt(10)
  console.log(mea);
  console.log(std);
  