[計量] PrepT2-PS-Q166

看板GMAT (GMAT入學考試)作者 (米尼)時間17年前 (2007/11/05 11:30), 編輯推噓3(301)
留言4則, 3人參與, 最新討論串1/1
166. 70, 75, 80, 85, 90, 105, 105, 130, 130, 130 The list shown consists of the times, in seconds, that it took each of 10 schoolchildren to run a distance of 400 meters. If the standard deviation of the 10 running times is 22.4 seconds, rounded to the nearest tenth of a second, how many of the 10 running times are more than 1 standard deviation below the mean of the 10 running times? (A) One (B) Two (C) Three (D) Four (E) Five 想請問一下這題該怎麼解~ 謝謝! -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 59.115.154.253

11/05 12:54, , 1F
答案是B嗎?
11/05 12:54, 1F

11/05 15:01, , 2F
Mean:100, 1 standard deviation lower=100-22.4=77.6
11/05 15:01, 2F

11/05 15:02, , 3F
所以兩人
11/05 15:02, 3F

11/05 16:47, , 4F
了解了~謝謝!
11/05 16:47, 4F
文章代碼(AID): #17BevM_e (GMAT)
文章代碼(AID): #17BevM_e (GMAT)