The world of mathematics.
What is the relationship?
John Martin is a ice cream seller.
He works in Pallmouth, a town next to the sea in Cornwall, in southwest England,
famous for its beautiful beaches and pleasant climate.
The ice cream seller is a business that depends on the good weather. Isn't that right?
The sky will be clear and sunny throughout the country.
The temperature will oscillate around 81 degrees Fahrenheit or 24 Celsius.
The winds will vary from light to moderate.
This is Radio BBC, Cornwall.
Today hundreds of people arrive to the beach due to high temperatures, and John is doing a good business.
But unfortunately, the English summers are not always like this.
Let's take the previous example.
A mathematical relationship?
Can a mathematical relationship be established between the temperature and the amount of ice cream that John sells in a day?
How can this relationship be investigated?
To find the relationship, we must first obtain data. John doesn't do it.
He only collects his ice cream in this factory, where an average of 12,000 liters is produced every day during the year.
Although they can store enough ice cream for six months,
producers need to know how the sales change due to the climate.
For example, in July 1990 in the Cornwall region, sales reached 68,000 liters.
The Meteorological Office keeps a statistics of the average temperature throughout the month of July.
In fact, there are statistics of each year that cover the last 330 years. Let's take the example of July 5.
There are two sets of data that we believe may have a relationship.
The temperature, that is, the number of degrees and the amount of liters of ice cream sold that day.
In other words, we have a couple of numbers associated with that day and a similar couple for each day in the sample.
Can we see this information in a more significant way?
Presenting information. How would you present it?
We can present this information through a graph, where the temperature that starts from 10 degrees will be found in the horizontal axis
and the ice cream sales represented in thousands of liters will be placed in the vertical axis.
This point indicates that on July 5, the average temperature in Cornwall was 18 degrees Celsius or 64 degrees Fahrenheit
and the number of liters of ice cream sold was 1,700.
In another day, the temperature was 19 degrees Celsius or 66 Fahrenheit and the ice cream sales reached 1,500 liters.
Each of these points corresponds to a different day.
Each day the average temperature and the total ice cream sales were recorded.
The points that were graphed are dispersed, so we call this type of graph a dispersion or dispersigram diagram.
Can we say that the ice cream sales increase if the day is warmer?
The answer is negative. This does not always happen.
For example, let's look at these two points.
This point shows the day when the average temperature was 21 degrees Celsius or about 72 degrees Fahrenheit
and the ice cream sales were 2,500 liters.
But the other point shows a day when the average temperature was 30 degrees Celsius or about 85 Fahrenheit.
But the ice cream sales were only 2,100 liters. Can you imagine what could have caused this?
We feel it, exhausted due to the heat wave.
Fortunately for John, this problem does not fully reflect reality.
Because the vast majority of the points in this strip do reflect an increase in sales when the temperature rises.
So we can say that this relationship is positive.
But not all relationships are positive.
It is a well-known fact that smoking is bad for our health.
If a woman smokes during pregnancy, what effect can it have on the baby that is not yet born?
Most women want to help their children by avoiding something that can affect them.
But when a pregnant woman smokes, she inhales a variety of toxic substances such as nicotine and carbon monoxide,
which are transmitted to the fetus.
Each of the toxic substances could deprive the baby of oxygen, which would lead to a weight loss when birth or even death.
Are these two factors related?
Women were interviewed by researchers about their smoking habits and the weight of their babies when they were born.
It was also discovered that mothers who smoke had babies that on average had about 200 grams less weight than mothers who do not smoke.
It was discovered that the more cigarettes a woman smokes, the lower the weight of the baby when birth.
We can describe this as a negative correlation.
Continuing with the topic of children's birth, let us remember that we all believed when we were little that stings bring babies.
For years, caricatures have contributed to the myth, describing them as a baby's delivery and delivery service.
The baby is born in a house.
According to a German belief, if a stinging woman flies over a house, a baby will be born there.
This relationship is as believed as the one that after the night follows the day.
When children ask where babies come from, they are told that stings take them from ponds and swamps, or that they were found in the caves of a rocky mountain and that they were released when they flew over the houses.
A group of scientists from the University of California decided to investigate the relationship between stings and babies.
They visited many large towns and cities and counted the number of stings living there.
They also traveled to towns and villages in the country's most remote areas.
They discovered that in the towns and cities where more stings were found, the number of births was higher.
Did the scientists find something true in the legend?
Is it correct to say that the number of stings really caused an increase in births?
The fact that there are more births where there are more stings does not mean that stings influence those births.
Finding a relationship between stings and babies does not mean that one thing really causes the other.
Why do you think the number of births is higher in areas where there are more stings?
And what other information do you have? How can you tell if they are related?
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