Author: BBC Radio 4

The Cuban government has announced that their population has fallen by 10% in two years ? just days after a demographer on the Caribbean island suggested an even bigger fall.

But which is the right number, and why are so many people leaving?

We speak to Dr Emily Morris from University College London and Dr Jorge Duany from the Cuban Research Institute at Florida International University.

Presenter: Kate Lamble Producer: Beth Ashmead Latham Series producer: Tom Colls Production co-ordinator: Katie Morrison Sound mix: Sue Maillot Editor: Richard Vadon

The claim we all swallow 5.5 grams of microplastic each week ? the same as the weight of a credit card ? has been repeated by charities, newspapers and the World Economic Forum.

But when you understand how this number was calculated, and the range of possible answers for the amount of plastic you eat, you might not want to repeat it yourself.

Professor Jamie Woodward from the University of Manchester explains what?s what.

Presenter: Kate Lamble Producer: Beth Ashmead Latham Researcher: Ajai Singh Series producer: Tom Colls Production co-ordinator: Katie Morrison Sound mix: Giles Aspen Editor: Richard Vadon

Recent reports claimed the average global mark-up, the difference between the price of production and the price that product is sold for, rose from 7% in 1980 to 59% by 2020.

So is this true? Are some companies choosing to charge us more than ever for their products?

We investigate the accuracy of these claims, and which companies are responsible with the help of Jan Eeckhout a Professor of Economics at Pompeu Fabra University in Barcelona

Presenter: Kate Lamble Producer: Beth Ashmead Latham Production co-ordinator: Katie Morrison Sound mix: Neil Churchill Editor: Richard Vadon

Canadian psychologist and culture war commentator Jordan Peterson says planet Earth has got 20% greener in the last 20 years.

But satellite data tells a different story.

We investigate the correct number, with the help of Dr Chi Chen, from Rutgers University in the US.

Presenter: Kate Lamble Series producer: Tom Colls Production co-ordinator: Brenda Brown Sound mix: Giles Aspen Editor: Richard Fenton-Smith

Researchers have catalogued 7,164 languages spoken around the world - some are used daily by billions. Half are spoken by less than 8000 people. The death of a language, when it?s no longer spoken as a first language by anyone living is a deeply significant moment in the cultural life of communities.

Multiple sources including the UN and National Geographic magazine have claimed this happens every two weeks. But we have reasons to be suspicious about that statistic. Gary Simons, executive editor of the Ethnologue language catalogue, explains where this idea came from.

Presenter: Kate Lamble Producer: Natasha Fernandes Series producer: Tom Colls Production co-ordinator: Brenda Brown Sound mix: Nigel Appleton Editor: Richard Fenton-Smith

The idea that women outnumber men by 14 to 1 as casualties of natural disasters has been repeated in newspapers and online for years - the UN have even used this statistic.

But when you track down the source, the research behind this claim leaves much to be desired.

Presenter: Kate Lamble Series producer: Tom Colls Production co-ordinator: Brenda Brown Sound mix: Nigel Appleton Editor: Richard Fenton-Smith

Is climate change making turbulence more dangerous for people taking flights around the world?

That?s what one listener asked, following a terrifying turbulence incident which left one person dead and more than 20 injured on a flight to Singapore.

We speak to turbulence expert Paul Williams, Professor of Atmospheric Science at the University of Reading, to understand what is going on.

Presenter: Kate Lamble Producer: Nathan Gower Series producer: Tom Colls Production co-ordinator: Brenda Brown Sound mix: Nigel Appleton Editor: Richard Vadon

How can tennis star Roger Federer have won only 54% of the points he played, but been the best player in the world? Jeff Sackmann, the tennis stats brain behind tennisabstract.com, explains to Tim Harford how probability works in the sport.

Presenter: Tim Harford Producer: Debbie Richford Series producer: Tom Colls Production co-ordinator: Brenda Brown Sound Mix: Nigel Appleton Editor: Richard Vadon

You might have found it boring in school maths classes, but Matt Parker thinks we should all learn to love trigonometry.

The ?Love Triangle? author talks to Tim Harford about the maths used in GPS, architecture and special effects.

Presenter: Tim Harford Producer: Debbie Richford Series Producer: Tom Colls Production Co-ordinator: Brenda Brown Sound Mix: Nigel Appleton Editor: Richard Vadon

Are Labour right about employment? Are the Conservatives right about cutting NHS managers? Are the Lib Dems right about share buyback? Are Reform UK right about their tax plans?

How do they make the exit poll so accurate?

What are the odds of meeting a very tall man in finance (with a trust fund)?

What does it mean that Roger Federer only won 54% of the points he played?

Tim Harford investigates some of the numbers in the news.

Presenter: Tim Harford Reporter: Kate Lamble Producers: Nathan Gower, Beth Ashmead Latham and Debbie Richford Series producer: Tom Colls Production coordinator: Brenda Brown Sound mix: Rod Farquhar Editor: Richard Vadon