abstract

This model is to discuss the influence of commodity specifications on commodity prices. This paper mainly analyzes the influence of packaging cost on commodity prices.

First, make assumptions to simplify the problem. Then set variables, build a model and solve it, and compare it with the actual investigation results. Finally, the model is discussed and the model error is analyzed.

Keywords: packaging; Commodity prices; Forecast;

problem description

Two groups of three kinds of the same goods with similar packaging but slightly different are studied, and a model describing the relationship between packaging and price is established.

Basic hypothesis

The influence of profit and other factors on commodity prices is not considered.

Packaging only calculates working hours and packaging materials.

Goods of different specifications have the same efficiency in packaging.

Different specifications of commodity packaging, appearance and packaging materials are similar, at least there is not much difference in price.

Parameters and variables

A: the cost of products in each commodity;

W: the content of products in each commodity;

B: the packaging cost of each commodity;

: input when packaging;

: packaging material cost;

S: dosage of packaging materials;

C(W): total cost;

C(W): the average cost per unit commodity;

Model derivation

According to common sense (1. 1)

By assuming 1 (1.2)

According to assumption 3 (1.3)

By assuming the area of 4 and (1.4)

Therefore, the formula (1. 1) gives (1.5).

This is the relationship between the total cost of goods and the set parameters.

So (1.6)

Solution of the model

According to theoretical deduction, if the product price is the price of two commodities, then

( 1.7)

One of them is.

Then (1.8)

model testing

Investigation time: 2011April 7.

Survey location: Wal-Mart in Zhichun Road

Commodity price survey

Commodity specifications and prices

Chacha melon seeds 150g 3.5

228 grams 5.3

250g 6.5

Qiqiang washing powder 400g 4

1 180g 1 1

1480g 13

Qiaqia guazi

From the measured value, bring it into the formula (1.8).

get

So (1.9)

Will be brought into the formula (1.9), and the actual value is 6.5.

Qiqiang washing powder

From the measured value, bring it into the formula (1.8).

get

So (1. 10)

Will be brought into the formula (1. 10), and the actual value is 13.

Error analysis and further discussion

As can be seen from the above discussion, the predicted price of Qiqiang washing powder is in good agreement with the actual price, and the relative error (∣ actual value-predicted value ∣/actual value) is only 5.3%. However, the predicted price of tea seeds is quite different from the actual price, and the relative error reaches 10.5%. The specific analysis is as follows:

1, the influence of profit equivalence factors on commodity prices can not be ignored.

2. The pricing of commodities is more complicated, such as checking melon seeds, which are original and creamy, so the predicted value is quite different from the actual value.

3. Because there is a gap between the cargo and the package of melon seeds, the error of formula (1.4) is large.