"Life expectancy" is the average age at death of the entire live-born population. In the middle of the nineteenth century, life expectancy in North America was 40 years, whereas now it is nearly 80 years. Thus, in those days, people must have been considered old at an age that we now consider the prime of life.
Which of the following, if true, undermines the argument above?
“Life expectancy” is the average age at death of the entire live-born population. In the middle of the nineteenth century, life expectancy in North America was 40 years, whereas now it is nearly 80 years. Thus, in those days, people must have been considered old at an age that we now consider the prime of life. Which of the following, if true, undermines the argument above? (A) In the middle of the nineteenth century, the population of North America was significantly smaller than it is today. (B) Most of the gains in life expectancy in the last 150 years have come from reductions in the number of infants who die in their first year of life. (C) Many of the people who live to an advanced age today do so only because of medical technology that was unknown in the nineteenth century. (D) The proportion of people who die in their seventies is significantly smaller today than is the proportion of people who die in their eighties. (E) More people in the middle of the nineteenth century engaged regularly in vigorous physical activity than do so today. B怎么和结论联系起来呢,A,D感觉是support但是不知道怎么解释,谢谢前辈们啊,急啊
Two group of people were born at the same time. In the first group, five infants died at age of 1. The other 5 died at the age of 79. The average age at death for the group is 40 years old. In the second group, all ten people died at the age of 80. The average age at death is 80. In group one, what age do you consider is an old age? 79. Not 40.
"Life expectancy" is the average age at death of the entire live-born population. In the middle of the nineteenth century, life expectancy in North America was 40 years, whereas now it is nearly 80 years. Thus, in those days people must have been considered old at an age that we now consider the prime of life.
b) Most of the gains in the life expectancy in the last 150 years have come from reductions in the number of infants who die in their first year of life.
Conclusion: People in older times (middle of 19th century or 150ish yrs ago), must have been considered old at an earlier age (e.g. someone who was 40 yrs old was considered old 150 yrs ago, which is considered a prime age now). B says, the average age at death has increased now because of lower infant death rates from 150 yrs ago. Thus, bringing the average age at death up in today's date.
Think of this as an Average/Mean problem in Quant, if a majority of elements in a set are 0, it brings the average down, when the 0 value elements are excluded, it brings the average up.