## Understanding Pandemic Statistics

Real examples help to better understand how to interpret the statistics.

False Positive Paradox: A particular medical test for a disease is 96% accurate. If one has the disease, the test comes back ‘Yes’ 96% of the time, and if one does not have the disease, the test comes back ‘Yes’ 4% of the time.

If  100  of 10000 tested patients have the disease, what is the probability that the person with the diagnosis ‘Yes’ has the disease?

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Effective Average Infection Ratio: R is the effective average infection ratio for a disease, also known as the reproduction number. It is the average number of secondary infections caused by one person. (Infections caused by the secondary infections – which would be tertiary infections – are not counted). Consider 50 infected people. Suppose 49 spread the infection to nobody, but one person spreads the infection to 60 people.

What is the R-value?

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Leslie Green asks: How would you propose to deal with the COVID-19 pandemic, given information current at the time of writing (11 October 2020).

A. Severe lockdown for 4 weeks

B. Ignore it and carry on as normal

C. Partial lockdown and wait for a vaccine

D. Some other idea

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The Pfizer COVID-19 vaccine-candidate interim results from 8 Nov 2020 showed 38,955 participants in a placebo controlled double-blind trial.
94 participants  became “evaluable”, which we presume to mean they showed COVID-19 symptoms. The analysis presented was that the vaccine efficacy rate was above 90%. What is the maximum number of (genuinely) vaccinated people who showed COVID-19 symptoms?

Variability Analysis on COVID-19 Interim Trial Data by Leslie Green

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Is there any rational justification for being wary of vaccines?

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In the UK, December 2020, up to 2 million university students were potentially going home for Xmas during the middle of the COVID-19 pandemic. A new fast COVID-19 test had been developed to spot the causative virus, SARS-CoV-2. These lateral flow tests had the characteristics shown in the image. At the time, around 1% of the population had the virus within the community.

The scientific advice, given on prime-time news channels, was that a pair of negative tests meant it was safe to go home, as a negative test meant a 99.75% chance of not having the virus.

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## WSJ: Mathematician is The Best Job

Starting from 2009, The Wall Street Journal repeats “Another day, another reason to get better at math.” Mathematicians top the list of the Best Job:

# The 10 Best Jobs of 2014

There are not many positions that are called “mathematician”. When you are good in math you work as a Problem Solver and have different titles: engineer, project manager, CIO, CTO, CEO, software engineer, business developer, etc.

Choose the Best Job = be good in Math!

## A+Click 2014 Numbers

2014 Annual Statistics

4600+ challenging problems for students in grades one through twelve;

500,000+ sessions on websites http://www.aplusclick.com and http://www.aplusclick.ru in 2014;

5’30” is the average duration of a session;

190 countries: USA 45%; India 9%; Canada 7%; Australia 5%; UK 5%;

10,000+ cities: top cities are  Brisbane, Australia; Chicago, USA; New Delhi, India;

25% visitors via mobile or tablets;

500 stars is the Best Score of the A+Click Challenge in 2014. Suhas, Bangalore, India is the best performer of 2014.

100 Best Performers of the A+Click Challenge in 2014: USA – 28%; Cambodia – 26%; India – 15%; Canada – 6%.

2,000+ people passed IQ Test; 454 people scored over 100;

100+ suggestions from users;

A+Click continues the adventure in 2015!

## How to Make Decisions: Slow or Fast?

The mind makes 35,000 decisions a day.

Half of all business decisions end in failure.

Data-centered decision-making results in 5-6% productivity increase.

Make your decision based on data and reasoning (when it is possible).

(c) 2014 Merit Career Development. http://www.meritcd.com

## Is probability useful in real life?

The question is simple. The best way to answer to the question is to give examples. Here they are:

How many cowboys are expected being alive after a gun fired in a saloon?

How many people in a block building have the same birthday as yours?

How much time do I expect to spend guessing a 5 digit password?

Does a prince have a chance to be chosen by a princess?

How much money does a casino earn everyday?

What is chance that a rocket launch will be successful?

Does a nuclear reactor explode if 4 of 100 its nuts fail?

We don’t use probability on daily basis. Sometimes, simple probabilistic calculations help us to make wise decision and avoid risk. My answer to the title’s question is YES. And yours?