The world of mathematics.
If the shoe fits, we don't always need shoes, but we will surely use them.
Ordinary shoes or shoes for special occasions.
When it comes to working shoes, who do you think is the one who suffers the most with
their feet?
The police?
The miners?
The athletes?
The
How does it feel?
It's fine. It's much more comfortable.
Well, support the foot in a flat way. How does it feel?
It feels much more comfortable around the tip.
Fortunately, most of us don't need a perfect fit like Melissa.
We can use shoes made in series.
Most shoes are made in a factory like this one.
About two million pairs are produced a year.
But are there enough people whose feet are the exact size to use each pair of shoes?
How big are the feet of the people?
If you had to measure the feet of a person as accurately as possible, what would you use?
What do you think the exact size should be?
Is it okay? How does it feel?
When you are sitting, your feet bear less weight than when you stand.
But when you stand and apply more pressure on your feet, they expand slightly.
When you exercise, your feet can expand even more.
Even with scientific purposes, measuring is enough to use approximations in millimeters.
These girls are part of a medical recognition to know how much the size of their body varies.
Even researchers can measure the length of internal parts of the body, such as the tibia or spinilla.
To compare the measurements, you must take a picture of the person standing and supporting the entire foot.
The calibrator has a screen that shows the length of the feet in millimeters.
The length of Amanda's left foot is 236 millimeters.
That's up to here.
It should be considered as a measurement of the nearest whole number.
What is the shortest length Amanda's foot could have?
And what is the longest?
It could be as short as 235.5 millimeters, or as long as 236.5 millimeters.
So it's between these two intervals.
Amanda was not the only girl whose foot was half 236 millimeters long.
Also Rhonda, Jackie, Linda, Maria, Sharon, Barbara, Carmen, Alicia, Julie, Felicia.
In total, there were 12 girls.
How many girls had their feet just one millimeter bigger?
Eight of them, from a sample of 200 girls.
What we have here is a frequency diagram.
Frequency means the number of girls for each one millimeter interval.
Apart from the scientists who study growth, who could all this information help?
Do they want it exactly this way?
How many different shoe measurements do you need in your life?
Surely you wouldn't want to buy a new pair of shoes every time your foot grows one millimeter.
While you're still growing, the length of your foot could be increasing to 8 millimeters per year.
That's approximately the third part of one inch.
Would that mean more than 100 different size shoes?
Only for you.
Jackie has chosen size number five, but she feels that it doesn't fit her.
Size five?
What exactly is size five?
It's an American shoe size.
In Great Britain, it would be size three and a half.
In both cases, it means that these shoe sizes are the closest to 227 millimeters,
that being the length of Jackie's foot.
In France, she would use size 37.
In the United States and Great Britain, a larger size, size five and a half from the United States or size four from Great Britain.
This is what she needs and it seems to be the most comfortable.
Let's go back to our chart.
Here we have the girls whose foot length is 227 millimeters.
So those girls whose feet are the same length as Jackie's or a little bigger, but smaller than 231 millimeters,
could wear a size five and a half shoe.
When it comes to shoes, we could put the size of these girls in a single column that goes beyond all those that have foot length that goes from 227 to 231 millimeters.
All of them would use size five and a half.
We can do the same for the other sizes.
Girls' shoe measurements.
The new diagram has less detail, since each column is wider.
Each one covers an interval of five millimeters that represents the shoe size.
Each shoe box contains coded information that includes the size.
This information is transmitted to the store directly to the factory.
With this information, the shoe company calculates not only the total sales of each model, but also the total number sold for each size.
With confidence, they can make the number of shoes they need to meet the demand of their future customers.
Mathematics in action.
But what about the length of the foot of the agent?
Could it be a frequency diagram similar to this program?
What could it do with other measurements, height, head size or arm length?