| 查看: 5708 | 回复: 18 | ||
[求助]
什么是negative control 什么是positive control？
|
||
| 什么是negative control 什么是positive control？ |
回复此楼» 猜你喜欢
云南大学材料与能源学院解琳课题组钙钛矿博士招生
已经有7人回复
-
西安交大新媒学院副院长用撤稿论文结题
已经有5人回复
-
论文撤稿了
已经有5人回复
-
某211大学教师把个人教师官方主页改成:我跑了我跑了我跑了!官宣跑路！
已经有5人回复
-
26/27申博自荐
已经有9人回复
-
售SCI一区T0P文章，我:8.O.5.5.1.O.5.4,科目齐全,可+急
已经有3人回复
-
售SCI一区T0P文章，我:8.O.5.5.1.O.5.4,科目齐全,可+急
已经有7人回复
-
河北省自然科学基金
已经有7人回复
-
揭秘青基评审内幕：几个A才能顺利中标
已经有4人回复
-
青B发送上会通知了吗
已经有7人回复
» 本主题相关价值贴推荐，对您同样有帮助:
- 转载的我认为当时最考研英语作文帮助最大的一篇文章，大家好好看看
已经有46人回复
- 双语阅读——人人都应该学习的20个软技能
已经有14人回复
- 编辑告诉我返回一个审稿意见？猜猜是positive还是negative？
已经有9人回复
TrickyVick
金虫 (小有名气)
- 应助: 14 (小学生)
- 金币: 810.5
- 红花: 6
- 帖子: 296
- 在线: 82.3小时
- 虫号: 2192184
- 注册: 2012-12-17
- 专业: 质谱分析
【答案】应助回帖
★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ...
感谢参与，应助指数 +1
zq254: 金币+100, ★有帮助, 10 2013-03-30 10:42:33
xbqewpq: 金币+1, 感谢应助~鼓励多交流~ 2013-03-30 10:59:48
感谢参与，应助指数 +1
zq254: 金币+100, ★有帮助, 10 2013-03-30 10:42:33
xbqewpq: 金币+1, 感谢应助~鼓励多交流~ 2013-03-30 10:59:48
|
举个例子， 你要测样品X里面有没有物质X Postive就是你把一定量的X加到确定没有X的溶液里做的样品 Negative就是你加的确定没有X的样品 Positive用来确定你的检测方法能否检测到物质X （一面方法不对或机器损坏造成的无法检测的情况） Negative用来确定你检测方法是否有相应的无关信号对应X ,比如某种杂质跟X在一个时间出来，那么你就需要在最后计算样品量的时候减去这个量。 |
8楼2013-03-26 17:08:03
TrickyVick
金虫 (小有名气)
- 应助: 14 (小学生)
- 金币: 810.5
- 红花: 6
- 帖子: 296
- 在线: 82.3小时
- 虫号: 2192184
- 注册: 2012-12-17
- 专业: 质谱分析
18楼2013-03-30 17:34:45
bwshanxi
至尊木虫 (文坛精英)
- 应助: 292 (大学生)
- 金币: 17070.1
- 红花: 18
- 帖子: 15795
- 在线: 879.4小时
- 虫号: 454546
- 注册: 2007-11-09
- 性别: GG
- 专业: 有机分子功能材料化学
6楼2013-03-25 23:12:53
7楼2013-03-26 08:28:36
9楼2013-03-27 06:52:27
黄黄050607
木虫 (著名写手)
- 应助: 9 (幼儿园)
- 金币: 1763.2
- 红花: 4
- 帖子: 1402
- 在线: 280.7小时
- 虫号: 2285769
- 注册: 2013-02-18
- 性别: GG
- 专业: 人力资源管理
10楼2013-03-27 07:25:55
XiaOliAngeR
木虫 (小有名气)
- 应助: 45 (小学生)
- 金币: 2785.8
- 红花: 2
- 帖子: 211
- 在线: 148.9小时
- 虫号: 1943725
- 注册: 2012-08-17
- 性别: GG
- 专业: 药物分析
2楼2013-03-25 22:42:16
XiaOliAngeR
木虫 (小有名气)
- 应助: 45 (小学生)
- 金币: 2785.8
- 红花: 2
- 帖子: 211
- 在线: 148.9小时
- 虫号: 1943725
- 注册: 2012-08-17
- 性别: GG
- 专业: 药物分析
3楼2013-03-25 22:46:01
 |
4楼2013-03-25 22:54:53
【答案】应助回帖
感谢参与，应助指数 +1
|
Negative Negative controls are groups where no phenomenon is expected. They ensure that there is no effect when there should be no effect. To continue with the example of drug testing, a negative control is a group that has not been administered the drug. We would say that the control group should show a negative or null effect. If the treatment group and the negative control both produce a negative result, it can be inferred that the treatment had no effect. If the treatment group and the negative control both produce a positive result, it can be inferred that a confounding variable acted on the experiment, and the positive results are likely not due to the treatment. [edit]Positive Positive controls are groups where a phenomenon is expected. That is, they ensure that there is an effect when there should be an effect, by using an experimental treatment that is already known to produce that effect (and then comparing this to the treatment that is being investigated in the experiment). Positive controls are often used to assess test validity. For example, to assess a new test's ability to detect a disease, then we can compare it against a different test that is already known to work. The well-established test is the positive control, since we already know that the answer to the question (whether the test works) is yes. Similarly, in an enzyme assay to measure the amount of an enzyme in a set of extracts, a positive control would be an assay containing a known quantity of the purified enzyme (while a negative control would contain no enzyme). The positive control should give a large amount of enzyme activity, while the negative control should give very low to no activity. If the positive control does not produce the expected result, there may be something wrong with the experimental procedure, and the experiment is repeated. For difficult or complicated experiments, the result from the positive control can also help in comparison to previous experimental results. For example, if the well-established disease test was determined to have the same effectiveness as found by previous experimenters, this indicates that the experiment is being performed in the same way that the previous experimenters did. When possible, multiple positive controls may be used - if there is more than one disease test that is known to be effective, more than one might be tested. Multiple positive controls also allow finer comparisons of the results (calibration, or standardization) if the expected results from the positive controls have different sizes. For example, in the enzyme assay discussed above, a standard curve may be produced by making many different samples with different quantities of the enzyme. From: http://en.wikipedia.org/wiki/Scientific_control |
5楼2013-03-25 23:08:08
10