| 查看: 905 | 回复: 3 | |||
| 本帖产生 1 个 翻译EPI ，点击这里进行查看 | |||
| 当前只显示满足指定条件的回帖，点击这里查看本话题的所有回帖 | |||
听涛月雨金虫 (小有名气)
|
[求助]
一小段数据统计分析的描述，欢迎应助
|
||
|
A geometric mean provides a better estimate of central tendency for data that are distributed with a long tail at the upper end of the distribution. This type of distribution is common in the measurement of environmental chemicals in blood or urine. The geometric mean is influenced less by high values than is the arithmetic mean. Geometric means were calculated by taking the log of each concentration and then computing the weighted mean of those log-transformed values using SUDAAN software. Ninety-five percent confidence intervals around this weighted mean were calculated by adding and subtracting an amount equal to the product of a Student’s t-statistic and the standard error of the weighted mean estimate. The degrees of freedom of the t-statistic were determined by subtracting the number of strata from the number of primary sampling units (PSUs) according to the data available from the complex survey design. The standard error was computed with SUDAAN’s Proc Descript (design=WR), which uses Taylor series linearization for variance estimation. The weighted geometric mean and its confidence limits were then obtained by taking the antilogs of this weighted mean and its upper and lower confidence limits. [ 来自科研家族 快乐检索 ] [ Last edited by 听涛月雨 on 2012-11-12 at 11:11 ] |
回复此楼» 猜你喜欢
什么时候开奖？
已经有4人回复
-
咱们一起用铁证分析2026国家社科基金中标与否
已经有27人回复
-
为什么余额宝的年化利率越来越低？主要原因有哪些？
已经有3人回复
-
2027广东省杰青
已经有9人回复
-
朋友圈看到的
已经有5人回复
-
欢迎发来filecode的Mz6后的代码验证其规律
已经有110人回复
-
明天放榜？
已经有5人回复
-
时间戳变了，能看出什么问题？
已经有11人回复
-
重要消息，中午系统在维护
已经有10人回复
-
投稿咨询
已经有6人回复
 |
4楼2012-11-13 08:37:54
fanliang1389
荣誉版主 (文坛精英)
有爱的二哥
- 翻译EPI: 57
- 应助: 18 (小学生)
- 贵宾: 1.989
- 金币: 13044.6
- 散金: 18540
- 红花: 123
- 沙发: 243
- 帖子: 18237
- 在线: 2429.4小时
- 虫号: 620773
- 注册: 2008-10-09
- 性别: GG
- 专业: 食品加工学基础
- 管辖: 博后之家
【答案】应助回帖
★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★
听涛月雨: 金币+10, 翻译EPI+1, ★有帮助, 有帮助，谢谢！但翻译的不是很好，很多统计术语没有翻译出来 2012-11-12 14:25:31
sltmac: 金币+20 2012-11-13 11:00:03
听涛月雨: 金币+10, 翻译EPI+1, ★有帮助, 有帮助，谢谢！但翻译的不是很好，很多统计术语没有翻译出来 2012-11-12 14:25:31
sltmac: 金币+20 2012-11-13 11:00:03
| 对于在顶端处有长间隔分布的数据，几何平均值可较好的估计该类数据的集中趋势。通常，这类分布用来测量血液和尿液中的环境化学物。与算术平均值相比，几何平均数更不易受大数值的影响。几何平均数计算方法如下：取各浓度的log值，然后采用SUDAAN软件计算经log转化后数值的加权平均数。通过加减学生t检验结果和加权平均数标准误差的平均数来计算加权平均数的95%置信区间。依据复杂取样设计中所取有效数据，初级抽样单位（PSUs）减去层数即为t-检验的自由度。采用SUDDAN Pro Descript(design=WR)计算标准误差，其原理为泰勒级数线性方差估计。加权平均数的反对数值即为加权几何平均数，加权平均数的上部和下部界限即为其置信界限。 |
2楼2012-11-12 13:45:54
3楼2012-11-12 23:00:08
