The challenge: What is cheap and what is expensive?

 

An important topic? I think so, especially considering that most of the programming traders either are not familiar with the basic trading rule "Buy low, sell high" or simply cannot translate it into program code. Otherwise, how can one explain numerous purchases on hawks? Inattention, greed, martingale?

Let's try to formulate together what is Cheap and what is Expensive? How do you understand it? How do you formalize it?

I suggest that we start by solving a simple task. The task is simplified, hypothetical, exaggerated, but the meaning, I think, will be clear:

We are at an agricultural market and our task is to buy five bags of potatoes (50 kg). We should buy them at the lowest possible price, so that we can sell them later without any problems. We go inside the market and see a long counter (100m). Behind the counter, along the side of it, there are 50 grandmothers sitting. Each woman sells sacks of potatoes for her own price, the prices are fixed, you cannot bargain, the sacks are all the same. Each woman has more than 5 sacks.

The thing is, we can only go to one side of the counter. If we see a new price, we cannot buy at the previous price, that is the condition of the problem. We have gone through 20 baskets and received the following price range (rub/bag): 650, 680, 750, 510, 480, 710, 620, 580, 490, 720, 670, 620, 890, 760, 790, 840, 680, 540, 610, 580.

So we have a range of prices. What will be your next steps? We don't know the further 30 prices yet. What further price will be your buying criterion? We still have 30 more dough ahead of us. We can either buy at some price (or prices - from different broads) or refuse to buy at all and go to another market.

What would you do? Below what price would you decide to "Buy"?
Or would you perhaps use some kind of system when buying potatoes and buy from several broads at once?


I am interested in all opinions. Besides, there are mathematically savvy people among the forum participants, and their opinions are especially interesting. How do you go about the markets and shops, gentlemen mathematicians?
Please, your opinions .....
I will express mine later.
 
DmitriyN:

An important topic? I think so, especially considering that most of the programming traders either are not familiar with the basic trading rule "Buy low, sell high" or simply cannot translate it into program code. Otherwise, how can one explain numerous purchases on hawks? Inattention, greed, martingale?

Let's try to formulate together what is Cheap and what is Expensive? How do you understand it? How do you formalize it?

I suggest that we start by solving a simple task. The task is simplified, hypothetical, exaggerated, but the meaning, I think, will be clear:

We are at an agricultural market and our task is to buy five bags of potatoes (50 kg). We should buy them at the lowest possible price, so that we can sell them later without any problems. We go inside the market and see a long counter (100m). Behind the counter, along the side of it, there are 50 grandmothers sitting. Each woman sells sacks of potatoes for her own price, the prices are fixed, you cannot bargain, the sacks are all the same. Each woman has more than 5 sacks.

The thing is, we can only go to one side of the counter. If we see a new price, we cannot buy at the previous price, that is the condition of the problem. We have gone through 20 baskets and received the following price range (rub/bag): 650, 680, 750, 510, 480, 710, 620, 580, 490, 720, 670, 620, 890, 760, 790, 840, 680, 540, 610, 580.

So we have a range of prices. What will be your next steps? We don't know the further 30 prices yet. What further price will be your buying criterion? We still have 30 more dough ahead of us. We can either buy at some price (or prices - from different broads) or refuse to buy at all and go to another market.

What would you do? Below what price would you decide to "Buy"?
Or would you perhaps use some kind of system when buying potatoes and buy from several broads at once?


I am interested in all opinions. Besides, there are mathematically savvy people among the forum participants, and their opinions are especially interesting. How do you go about the markets and shops, gentlemen mathematicians?
Please, your opinions .....
I will express mine later.


Your post is insulting to women
 
DmitriyN:

Firstly - there are a lot of restrictions (can't go backwards and so on) for the case described (although I know what you mean)

Secondly, it very much depends on what price we can or have the ability to sell for and for how long.

Thirdly, we can buy in autumn at any suggested price, and in winter or spring, having saved the goods, sell them at 5 times the price without complicated mathematical calculations....))))

 
DmitriyN:

What would you do?

I would buy at the average market price
 
It's not just a mate problem, it's a trick. I think so. Because the condition is very strange.
 
The price above which I would sell, below which I would buy was changing as information was added, and not the average. and it cannot be called a history analysis, the trades are here and now simultaneously. so time does not appear here.
 
LeoV:
1. Yes, this is an analogy;
2. Regarding the selling price (or prices of sales), of course we don't know anything, we only know the prices that are available (20 prices);
3. this is also a solution, but it does not apply to all analogies.
 
fozi:
I would buy at the average market price
Then the question is: Can we then sell at or above the average price? Or should we buy cheaper than the average price? How can we determine the optimal price?
 
If you make an analogy with hashing, then on each countdown here and now you select those pairs, whether they are triangles or more complex hedges, the amplitude of the differences between which and between the instrument itself, which is being hashed, will be maximum and minimum.
 
Niket:
Here time has been replaced by space, the length of the counter (yes, a trick question). What to do with the new data? There are several options: use them, don't use them, partially use them.
 
550 purchase, 800 sale