## #StackBounty: #terminology #observational-study #communication Term for observational study in which different cohorts are compared at …

### Bounty: 50

I have a dataset tracking certain outcomes in school children, with all grades being sampled every year for a number of years. There are a number of study designs possible with such a dataset. As I understand it:

Cross-sectional designs would compare, say, different grade at a fixed point in time. For example, they could compare 2018 grade 7 students, 2018 grade 8 students and 2018 grade 9 students.

Longitudinal designs would compare, a single cohort of students across time. For example, they could compare 2016 grade 6 students, 2017 grade 7 students and 2018 grade 8 students.

Is there an analogous term for a design which compares students in a given grade across calendar years?

For example, comparing 2016 year 7 students, 2017 year 7 students and 2018 year 7 students. It is somewhat longitudinal because there is a temporal comparison happening but it isn’t the same as in the longitudinal design described above. Is there common terminology one could use to distinguish between the two?

(In this question ‘grade’ is used to refer to the year level of the student in school, not to a mark on academic assessment.)

Get this bounty!!!

## #StackBounty: #p-value #intuition #application #communication #climate Evidence for man-made global warming hits 'gold standard&#39…

### How should we interpret the $$5sigma$$ threshold in this research on climate change?

This message in a Reuter’s article from 25 february is currently all over the news:

They said confidence that human activities were raising the heat at the Earth’s surface had reached a “five-sigma” level, a statistical gauge meaning there is only a one-in-a-million chance that the signal would appear if there was no warming.

I believe that this refers to this article “Celebrating the anniversary of three key events in climate change science” which contains a plot, which is shown schematically below (It is a sketch because I could not find an open source image for an original, similar free images are found here). Another article from the same research group, which seems to be a more original source, is here (but it uses a 1% significance instead of $$5sigma$$).

The plot presents measurements from three different research groups: 1 Remote Sensing Systems, 2 the Center for Satellite Applications and Research, and the 3 University of Alabama at Huntsville.

The plot displays three rising curves of signal to noise ratio as a function of trend length.

So somehow scientists have measured an anthropogenic signal of global warming (or climate change?) at a $$5sigma$$ level, which is apparently some scientific standard of evidence.

For me such graph, which has a high level of abstraction, raises many questions$$^{dagger}$$, and in general I wonder about the question ‘How did they do this?’. How do we explain this experiment into simple words (but not so abstract) and also explain the meaning of the $$5sigma$$ level?

I ask this question here because I do not want a discussion about climate. Instead I want answers regarding the statistical content and especially to clarify the meaning of such a statement that is using/claiming $$5 sigma$$.

$$^dagger$$:What is the null hypothesis? How did they set up the experiment to get a anthropogenic signal? What is the effect size of the signal? Is it just a small signal and we only measure this now because the noise is decreasing, or is the signal increasing? What kind of assumptions are made to create the statistical model by which they determine the crossing of a 5 sigma threshold (independence, random effects, etc…)? Why are the three curves for the different research groups different, do they have different noise or do they have different signals, and in the case of the latter, what does that mean regarding the interpretation of probability and external validity?

Get this bounty!!!

## #StackBounty: #p-value #intuition #application #communication #climate Evidence for man-made global warming hits 'gold standard&#39…

### How should we interpret the $$5sigma$$ threshold in this research on climate change?

This message in a Reuter’s article from 25 february is currently all over the news:

They said confidence that human activities were raising the heat at the Earth’s surface had reached a “five-sigma” level, a statistical gauge meaning there is only a one-in-a-million chance that the signal would appear if there was no warming.

I believe that this refers to this article “Celebrating the anniversary of three key events in climate change science” which contains a plot, which is shown schematically below (It is a sketch because I could not find an open source image for an original, similar free images are found here). Another article from the same research group, which seems to be a more original source, is here (but it uses a 1% significance instead of $$5sigma$$).

The plot presents measurements from three different research groups: 1 Remote Sensing Systems, 2 the Center for Satellite Applications and Research, and the 3 University of Alabama at Huntsville.

The plot displays three rising curves of signal to noise ratio as a function of trend length.

So somehow scientists have measured an anthropogenic signal of global warming (or climate change?) at a $$5sigma$$ level, which is apparently some scientific standard of evidence.

For me such graph, which has a high level of abstraction, raises many questions$$^{dagger}$$, and in general I wonder about the question ‘How did they do this?’. How do we explain this experiment into simple words (but not so abstract) and also explain the meaning of the $$5sigma$$ level?

I ask this question here because I do not want a discussion about climate. Instead I want answers regarding the statistical content and especially to clarify the meaning of such a statement that is using/claiming $$5 sigma$$.

$$^dagger$$:What is the null hypothesis? How did they set up the experiment to get a anthropogenic signal? What is the effect size of the signal? Is it just a small signal and we only measure this now because the noise is decreasing, or is the signal increasing? What kind of assumptions are made to create the statistical model by which they determine the crossing of a 5 sigma threshold (independence, random effects, etc…)? Why are the three curves for the different research groups different, do they have different noise or do they have different signals, and in the case of the latter, what does that mean regarding the interpretation of probability and external validity?

Get this bounty!!!

## #StackBounty: #p-value #intuition #application #communication #climate Evidence for man-made global warming hits 'gold standard&#39…

### How should we interpret the $$5sigma$$ threshold in this research on climate change?

This message in a Reuter’s article from 25 february is currently all over the news:

They said confidence that human activities were raising the heat at the Earth’s surface had reached a “five-sigma” level, a statistical gauge meaning there is only a one-in-a-million chance that the signal would appear if there was no warming.

I believe that this refers to this article “Celebrating the anniversary of three key events in climate change science” which contains a plot, which is shown schematically below (It is a sketch because I could not find an open source image for an original, similar free images are found here). Another article from the same research group, which seems to be a more original source, is here (but it uses a 1% significance instead of $$5sigma$$).

The plot presents measurements from three different research groups: 1 Remote Sensing Systems, 2 the Center for Satellite Applications and Research, and the 3 University of Alabama at Huntsville.

The plot displays three rising curves of signal to noise ratio as a function of trend length.

So somehow scientists have measured an anthropogenic signal of global warming (or climate change?) at a $$5sigma$$ level, which is apparently some scientific standard of evidence.

For me such graph, which has a high level of abstraction, raises many questions$$^{dagger}$$, and in general I wonder about the question ‘How did they do this?’. How do we explain this experiment into simple words (but not so abstract) and also explain the meaning of the $$5sigma$$ level?

I ask this question here because I do not want a discussion about climate. Instead I want answers regarding the statistical content and especially to clarify the meaning of such a statement that is using/claiming $$5 sigma$$.

$$^dagger$$:What is the null hypothesis? How did they set up the experiment to get a anthropogenic signal? What is the effect size of the signal? Is it just a small signal and we only measure this now because the noise is decreasing, or is the signal increasing? What kind of assumptions are made to create the statistical model by which they determine the crossing of a 5 sigma threshold (independence, random effects, etc…)? Why are the three curves for the different research groups different, do they have different noise or do they have different signals, and in the case of the latter, what does that mean regarding the interpretation of probability and external validity?

Get this bounty!!!

## #StackBounty: #p-value #intuition #application #communication #climate Evidence for man-made global warming hits 'gold standard&#39…

### How should we interpret the $$5sigma$$ threshold in this research on climate change?

This message in a Reuter’s article from 25 february is currently all over the news:

They said confidence that human activities were raising the heat at the Earth’s surface had reached a “five-sigma” level, a statistical gauge meaning there is only a one-in-a-million chance that the signal would appear if there was no warming.

I believe that this refers to this article “Celebrating the anniversary of three key events in climate change science” which contains a plot, which is shown schematically below (It is a sketch because I could not find an open source image for an original, similar free images are found here). Another article from the same research group, which seems to be a more original source, is here (but it uses a 1% significance instead of $$5sigma$$).

The plot presents measurements from three different research groups: 1 Remote Sensing Systems, 2 the Center for Satellite Applications and Research, and the 3 University of Alabama at Huntsville.

The plot displays three rising curves of signal to noise ratio as a function of trend length.

So somehow scientists have measured an anthropogenic signal of global warming (or climate change?) at a $$5sigma$$ level, which is apparently some scientific standard of evidence.

For me such graph, which has a high level of abstraction, raises many questions$$^{dagger}$$, and in general I wonder about the question ‘How did they do this?’. How do we explain this experiment into simple words (but not so abstract) and also explain the meaning of the $$5sigma$$ level?

I ask this question here because I do not want a discussion about climate. Instead I want answers regarding the statistical content and especially to clarify the meaning of such a statement that is using/claiming $$5 sigma$$.

$$^dagger$$:What is the null hypothesis? How did they set up the experiment to get a anthropogenic signal? What is the effect size of the signal? Is it just a small signal and we only measure this now because the noise is decreasing, or is the signal increasing? What kind of assumptions are made to create the statistical model by which they determine the crossing of a 5 sigma threshold (independence, random effects, etc…)? Why are the three curves for the different research groups different, do they have different noise or do they have different signals, and in the case of the latter, what does that mean regarding the interpretation of probability and external validity?

Get this bounty!!!

## #StackBounty: #p-value #intuition #application #communication #climate Evidence for man-made global warming hits 'gold standard&#39…

### How should we interpret the $$5sigma$$ threshold in this research on climate change?

This message in a Reuter’s article from 25 february is currently all over the news:

They said confidence that human activities were raising the heat at the Earth’s surface had reached a “five-sigma” level, a statistical gauge meaning there is only a one-in-a-million chance that the signal would appear if there was no warming.

I believe that this refers to this article “Celebrating the anniversary of three key events in climate change science” which contains a plot, which is shown schematically below (It is a sketch because I could not find an open source image for an original, similar free images are found here). Another article from the same research group, which seems to be a more original source, is here (but it uses a 1% significance instead of $$5sigma$$).

The plot presents measurements from three different research groups: 1 Remote Sensing Systems, 2 the Center for Satellite Applications and Research, and the 3 University of Alabama at Huntsville.

The plot displays three rising curves of signal to noise ratio as a function of trend length.

So somehow scientists have measured an anthropogenic signal of global warming (or climate change?) at a $$5sigma$$ level, which is apparently some scientific standard of evidence.

For me such graph, which has a high level of abstraction, raises many questions$$^{dagger}$$, and in general I wonder about the question ‘How did they do this?’. How do we explain this experiment into simple words (but not so abstract) and also explain the meaning of the $$5sigma$$ level?

I ask this question here because I do not want a discussion about climate. Instead I want answers regarding the statistical content and especially to clarify the meaning of such a statement that is using/claiming $$5 sigma$$.

$$^dagger$$:What is the null hypothesis? How did they set up the experiment to get a anthropogenic signal? What is the effect size of the signal? Is it just a small signal and we only measure this now because the noise is decreasing, or is the signal increasing? What kind of assumptions are made to create the statistical model by which they determine the crossing of a 5 sigma threshold (independence, random effects, etc…)? Why are the three curves for the different research groups different, do they have different noise or do they have different signals, and in the case of the latter, what does that mean regarding the interpretation of probability and external validity?

Get this bounty!!!

## #StackBounty: #p-value #intuition #application #communication #climate Evidence for man-made global warming hits 'gold standard&#39…

### How should we interpret the $$5sigma$$ threshold in this research on climate change?

This message in a Reuter’s article from 25 february is currently all over the news:

They said confidence that human activities were raising the heat at the Earth’s surface had reached a “five-sigma” level, a statistical gauge meaning there is only a one-in-a-million chance that the signal would appear if there was no warming.

I believe that this refers to this article “Celebrating the anniversary of three key events in climate change science” which contains a plot, which is shown schematically below (It is a sketch because I could not find an open source image for an original, similar free images are found here). Another article from the same research group, which seems to be a more original source, is here (but it uses a 1% significance instead of $$5sigma$$).

The plot presents measurements from three different research groups: 1 Remote Sensing Systems, 2 the Center for Satellite Applications and Research, and the 3 University of Alabama at Huntsville.

The plot displays three rising curves of signal to noise ratio as a function of trend length.

So somehow scientists have measured an anthropogenic signal of global warming (or climate change?) at a $$5sigma$$ level, which is apparently some scientific standard of evidence.

For me such graph, which has a high level of abstraction, raises many questions$$^{dagger}$$, and in general I wonder about the question ‘How did they do this?’. How do we explain this experiment into simple words (but not so abstract) and also explain the meaning of the $$5sigma$$ level?

I ask this question here because I do not want a discussion about climate. Instead I want answers regarding the statistical content and especially to clarify the meaning of such a statement that is using/claiming $$5 sigma$$.

$$^dagger$$:What is the null hypothesis? How did they set up the experiment to get a anthropogenic signal? What is the effect size of the signal? Is it just a small signal and we only measure this now because the noise is decreasing, or is the signal increasing? What kind of assumptions are made to create the statistical model by which they determine the crossing of a 5 sigma threshold (independence, random effects, etc…)? Why are the three curves for the different research groups different, do they have different noise or do they have different signals, and in the case of the latter, what does that mean regarding the interpretation of probability and external validity?

Get this bounty!!!

## #StackBounty: #p-value #intuition #application #communication #climate Evidence for man-made global warming hits 'gold standard&#39…

### How should we interpret the $$5sigma$$ threshold in this research on climate change?

This message in a Reuter’s article from 25 february is currently all over the news:

They said confidence that human activities were raising the heat at the Earth’s surface had reached a “five-sigma” level, a statistical gauge meaning there is only a one-in-a-million chance that the signal would appear if there was no warming.

I believe that this refers to this article “Celebrating the anniversary of three key events in climate change science” which contains a plot, which is shown schematically below (It is a sketch because I could not find an open source image for an original, similar free images are found here). Another article from the same research group, which seems to be a more original source, is here (but it uses a 1% significance instead of $$5sigma$$).

The plot presents measurements from three different research groups: 1 Remote Sensing Systems, 2 the Center for Satellite Applications and Research, and the 3 University of Alabama at Huntsville.

The plot displays three rising curves of signal to noise ratio as a function of trend length.

So somehow scientists have measured an anthropogenic signal of global warming (or climate change?) at a $$5sigma$$ level, which is apparently some scientific standard of evidence.

For me such graph, which has a high level of abstraction, raises many questions$$^{dagger}$$, and in general I wonder about the question ‘How did they do this?’. How do we explain this experiment into simple words (but not so abstract) and also explain the meaning of the $$5sigma$$ level?

I ask this question here because I do not want a discussion about climate. Instead I want answers regarding the statistical content and especially to clarify the meaning of such a statement that is using/claiming $$5 sigma$$.

$$^dagger$$:What is the null hypothesis? How did they set up the experiment to get a anthropogenic signal? What is the effect size of the signal? Is it just a small signal and we only measure this now because the noise is decreasing, or is the signal increasing? What kind of assumptions are made to create the statistical model by which they determine the crossing of a 5 sigma threshold (independence, random effects, etc…)? Why are the three curves for the different research groups different, do they have different noise or do they have different signals, and in the case of the latter, what does that mean regarding the interpretation of probability and external validity?

Get this bounty!!!

## #StackBounty: #p-value #intuition #application #communication #climate Evidence for man-made global warming hits 'gold standard&#39…

### How should we interpret the $$5sigma$$ threshold in this research on climate change?

This message in a Reuter’s article from 25 february is currently all over the news:

They said confidence that human activities were raising the heat at the Earth’s surface had reached a “five-sigma” level, a statistical gauge meaning there is only a one-in-a-million chance that the signal would appear if there was no warming.

I believe that this refers to this article “Celebrating the anniversary of three key events in climate change science” which contains a plot, which is shown schematically below (It is a sketch because I could not find an open source image for an original, similar free images are found here). Another article from the same research group, which seems to be a more original source, is here (but it uses a 1% significance instead of $$5sigma$$).

The plot presents measurements from three different research groups: 1 Remote Sensing Systems, 2 the Center for Satellite Applications and Research, and the 3 University of Alabama at Huntsville.

The plot displays three rising curves of signal to noise ratio as a function of trend length.

So somehow scientists have measured an anthropogenic signal of global warming (or climate change?) at a $$5sigma$$ level, which is apparently some scientific standard of evidence.

For me such graph, which has a high level of abstraction, raises many questions$$^{dagger}$$, and in general I wonder about the question ‘How did they do this?’. How do we explain this experiment into simple words (but not so abstract) and also explain the meaning of the $$5sigma$$ level?

I ask this question here because I do not want a discussion about climate. Instead I want answers regarding the statistical content and especially to clarify the meaning of such a statement that is using/claiming $$5 sigma$$.

$$^dagger$$:What is the null hypothesis? How did they set up the experiment to get a anthropogenic signal? What is the effect size of the signal? Is it just a small signal and we only measure this now because the noise is decreasing, or is the signal increasing? What kind of assumptions are made to create the statistical model by which they determine the crossing of a 5 sigma threshold (independence, random effects, etc…)? Why are the three curves for the different research groups different, do they have different noise or do they have different signals, and in the case of the latter, what does that mean regarding the interpretation of probability and external validity?

Get this bounty!!!

## #StackBounty: #p-value #intuition #application #communication #climate Evidence for man-made global warming hits 'gold standard&#39…

### How should we interpret the $$5sigma$$ threshold in this research on climate change?

This message in a Reuter’s article from 25 february is currently all over the news:

They said confidence that human activities were raising the heat at the Earth’s surface had reached a “five-sigma” level, a statistical gauge meaning there is only a one-in-a-million chance that the signal would appear if there was no warming.

I believe that this refers to this article “Celebrating the anniversary of three key events in climate change science” which contains a plot, which is shown schematically below (It is a sketch because I could not find an open source image for an original, similar free images are found here). Another article from the same research group, which seems to be a more original source, is here (but it uses a 1% significance instead of $$5sigma$$).

The plot presents measurements from three different research groups: 1 Remote Sensing Systems, 2 the Center for Satellite Applications and Research, and the 3 University of Alabama at Huntsville.

The plot displays three rising curves of signal to noise ratio as a function of trend length.

So somehow scientists have measured an anthropogenic signal of global warming (or climate change?) at a $$5sigma$$ level, which is apparently some scientific standard of evidence.

For me such graph, which has a high level of abstraction, raises many questions$$^{dagger}$$, and in general I wonder about the question ‘How did they do this?’. How do we explain this experiment into simple words (but not so abstract) and also explain the meaning of the $$5sigma$$ level?

I ask this question here because I do not want a discussion about climate. Instead I want answers regarding the statistical content and especially to clarify the meaning of such a statement that is using/claiming $$5 sigma$$.

$$^dagger$$:What is the null hypothesis? How did they set up the experiment to get a anthropogenic signal? What is the effect size of the signal? Is it just a small signal and we only measure this now because the noise is decreasing, or is the signal increasing? What kind of assumptions are made to create the statistical model by which they determine the crossing of a 5 sigma threshold (independence, random effects, etc…)? Why are the three curves for the different research groups different, do they have different noise or do they have different signals, and in the case of the latter, what does that mean regarding the interpretation of probability and external validity?

Get this bounty!!!