2. 外语
  3. Closing prices for a certain stock were recorded each day for a week in the table above. If the monthly average (arithmetic mean

Closing prices for a certain stock were recorded each day for a week in the table above. If the monthly average (arithmetic mean

admin2011-01-18  62
问题 Closing prices for a certain stock were recorded each day for a week in the table above. If the monthly average (arithmetic mean) was 18.43 and the standard deviation was 0.27, how many days during this week did the closing price fall within two standard deviations from the average?
选项 A、1
B、2
C、3
D、4
E、5
答案C
解析 Since two standard deviations away from the mean works out to 18.43-0.27×2=17.89, there are 3 days during which the stock prices fell between 17.89 and 18.43: Monday, Tuesday, and Wednesday. We really don’t have to worry about prices above the mean, because there were none of them during this time frame.
转载请注明原文地址:https://kaotiyun.com/show/9JtO777K
本试题收录于： GMAT QUANTITATIVE题库GMAT分类
0

GMAT QUANTITATIVE

GMAT

相关试题推荐
随机试题
最新回复(0)