OG上的一道数学题的错题记录。

M186UID: 3954742

OG数学练习中，
5. Eight hundred insects were weighed, and the resulting measurements, in
milligrams, are summarized in the boxplot below.
(a) What are the range, the three quartiles, and the interquartile range of the
measurements?
(b) If the 80th percentile of the measurements is 130 milligrams, about how
many measurements are between 126 milligrams and 130 milligrams?

答案
5. (a) range = 41, Q1 2 3 = 114, Q = 118, Q = 126, interquartile range = 12
(b) 40 measurements


疑问：(a)会做，（b)我的思路是： Q3即75th,值为126， 80th的值为130，126到130中测量数占总的样本总数为 80%-75%=5%， 因此，126到130的测量数为： 800*5% = 40，可是我竟然将总数eight hundred想当然地看成了100。从而导致出错。由此可见，数学是很容易丢分的。