Heart ratetracking for three of the Alaska bears showed a drop from 55 beats per minute on average before hibernation to 14 erratic ones per minute in winter.
And for the purposes of investment decisions, the second group didn't matter; tracking its spending habits or worrying over its savings rate was a waste of time.
投资决策的目的，第二种人并不关心。调查他们的消费习惯，关心他们的储蓄率根本就是浪费时间。
3
Tracking the changing "price" of women, Mr. Porter turns his eye to America's fertility rate, which went into steep decline around 1970.