text: const MODERN_ACTIVITY= 15; 
  const HALF_LIFE_PERIOD= 5730;
  
  module.exports = function dateSample(sampleActivity) {
    if(sampleActivity === undefined || typeof sampleActivity !== "string" || !parseFloat(sampleActivity) || parseFloat(sampleActivity) <= 0 || parseFloat(sampleActivity) >= MODERN_ACTIVITY) {
      return false;
    } else {
      return Math.ceil(Math.log(MODERN_ACTIVITY / parseFloat(sampleActivity)) / (0.693 / HALF_LIFE_PERIOD));
    }
  };
  