Introduction to Statistical Literacy

class: center, middle, inverse, title-slide

# Introduction to Statistical Literacy
## Analyse et traitement de l’information   Comprendre le numérique
### Stéphane Guerrier
### 28 October 2021

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# What is statistics?

.pull-left[
.smaller[.hi-pink[Statistics] is a science that uses mathematics and computer science to deal with the collection, analysis, interpretation, and presentation of masses of numerical data. Informally, it is the .pink[science of learning from data]. 🧐]
<img src="pics/stat.jpeg" width="90%" style="display: block; margin: auto;" />
.tiny[Source: [luminousmen](luminousmen.com)]
]

.pull-right[
.smaller[.hi-purple[Statistics] is a crucial part of our life. However, .purple[statistical methods are often consciously (or not) misused] (but how? 🤔). This can lead to contradictory studies and conclusions (as seen during the current COVID-19 pandemic).]

.tiny[Source: [Atoz Markets](https://atozmarkets.com/news/untold-reality-of-p-hacking-in-finance/)]

]

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# What is statistical literacy?

.smallest[.hi-pink[Statistical Literacy] can be defined as follows:]
- .smallest[The ability to .pink[understand data], or arguments that use data.]
- .smallest[Being able to apply .pink[critical thinking] about numbers and about .pink[statistics used as evidence in arguments].]
- .smallest[Understanding how statistical associations are used to assess causal connections.]

.pull-left[
<img src="pics/correlation.png" width="100%" style="display: block; margin: auto;" />
]

.pull-right[
.tiny[Source: [xkcd](xkcd.com/552)]

👋 .smallest[If you want to know more about these comic strips take a look [here](https://www.explainxkcd.com/wiki/index.php/552:_Correlation).]
]

.smallest[.hi-purple[Statistical literacy is now becoming an essential skill]. It is, for example, needed by .purple[anyone who tries to learn new information from data]. .turquoise[Scientists also need to develop statistical literacy so that they can produce both rigorous and reproducible research.]]

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# (Mis)Understanding statistical results

.tiny[Source: [xkcd](xkcd.com/795)]

👋 .smaller[If you want to know more about these comic strips take a look [here](https://www.explainxkcd.com/wiki/index.php/795:_Conditional_Risk).]

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# How can statistics be useful?

As mentioned previously, statistics is the .pink[science of learning from data]. It can be used (among others) to:
1. .purple[Visualize data] (e.g. propagation of COVID-19 in different countries).
2. .purple[Understand and interpret data] (e.g. main causes of cancer). 
3. .purple[Make predictions] (e.g. predicting unemployment or risk indices).
4. .hi-pink[Assess the validity of a hypothesis].

In this class, we will focus on the last point:
''.pink[*how to assess the validity of a hypothesis using statistics?*]''. More precisely, we will discuss how statistical methods can be used to evaluate claims (hypotheses) such as:

1. Coffee consumption increases blood pressure (really 🙄 ☕?).
2. Republican politicians are bad/good for the American Economy.
3. A glass of red wine is as good as an hour at the gym (🍷 🏃 😆).

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# How does it work?

- Statistical methods are based on several fundamental concepts, the most central of which is to consider the information available (in the form of data) resulting from a .hi-pink[random process]. 🙉
- As such, the data represent a .hi-turquoise[random sample] of a totally or conceptually accessible .hi-turquoise[population].

.tiny[Source: [luminousmen](luminousmen.com)]

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# How does it work?

- Statistics allows to determine the .hi-pink[decision-making risks] (in the form of probabilities) associated with learning (decisions) based on the analysis of data extracted from samples. .slate[This allows to evaluate the validity of a claim] (such as the ones we discussed previously). 
- .purple[Understanding and knowing how to interpret statistical analyses is therefore becoming an increasingly vital skill].
- In some sense, .hi-pink[statistics plays a crucial role in our life] as new discoveries (obtained using statistical methods) directly impact us<sup>.smallest[👋]</sup>.
- However, understanding statistical results is not intuitive. There exist many pitfalls such as .purple[p-hacking] or .purple[HARKing] (e.g. why are there so many contradictory studies? Is Hydroxychloroquine working or not?).

.footnote[.smallest[👋] This  is essentially true in the area of .hi-purple[Big Data] where the discovery of patterns and/or signals hidden in massive amounts of data is increasingly becoming one of the major challenges faced by modern scientific research.]

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# So many studies?

.turquoise["*A glass of red wine is as good as an hour at the gym*"?] 🙄

.tiny[Source: Scientific Studies: Last Week Tonight with John Oliver (HBO)]

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# Contraditory studies?

.turquoise[What about coffee? Is it good?]

.tiny[Source: Scientific Studies: Last Week Tonight with John Oliver (HBO)]

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# So everything causes cancer?

.footnote[.smallest[👋] Read the original article: "*This is why you shouldn’t believe that exciting new medical study*" [here](https://www.vox.com/2015/3/23/8264355/research-study-hype).]

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# What are the consequences?

.turquoise[Which study should I pick?]

.tiny[Source: Scientific Studies: Last Week Tonight with John Oliver (HBO)]

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# The Hydroxychloroquine Controversy 🦠

.smallest[Since the beginning of 2020, various research teams have suggested that (hydroxy)chloroquine combined with other drugs (e.g. azithromycin) is an .hi-pink[effective treatment] for the coronavirus disease 2019. Since then there have been .hi-purple[many many many contradictory publications] (and some [retractions](https://en.wikipedia.org/wiki/The_Lancet#Retracted_papers_and_scientific_controversies)!) and the efficacy of these drugs remains unclear. The timeline can be found [here](https://en.wikipedia.org/wiki/Chloroquine_and_hydroxychloroquine_during_the_COVID-19_pandemic).]

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