Implementation of multiple linear regression to estimate profit on sales of screen printing equipment

Traditional marketing strategies are no longer practical to implement because the process requires more costs and longer time to disseminate information. Marketing strategy is one of the key aspects of business success, be it for large or small companies. An effective marketing strategy must be able to attract consumer attention, build brand awareness, increase sales, and strengthen the company’s market position. In developing a marketing strategy, it is necessary to carry out market and competitor analysis, determine market targets, determine product or service positioning, choose the right distribution channel, determine the appropriate price, and develop an effective promotional program. In the digital era, marketing strategies must also include the use of computer technology. Data mining is a science that discusses knowledge from previous data to estimate the amount of production in the future. Data mining is a term used to find hidden knowledge in databases. “Data mining is a semi-automated process using statistics, mathematics, artificial intelligence and machine learning techniques to extract and identify valuable and useful information in large databases. For this reason, it is necessary to solve this problem by using one of the five methods in the field of Data Mining, namely the multiple linear regression method, where this method will analyze the influential variables and can make estimates. Multiple linear regression is a method that can be used to analyze data and obtain meaningful conclusions about a relationship between one variable and another. This relationship is generally expressed by a mathematical equation which states the relationship between the independent and dependent variables in the form of a simple equation.


I. INTRODUCTION
Screen printing is printing ink on the top of the t-shirt media with tools such as screens or screen printing film [1]. At this time, the telang t-shirt screen printing service has developed into a particular type of business that is quite promising because there are more and more orders for t-shirt screen printing, ranging from just merchandise, the interests of an event, for community uniforms, to campaign purposes. The screen-printing business is increasingly growing and expanding day by day. This business is increasingly favored by the community, especially among young people. Various types of screen-printing businesses, screen printing, is a printing process technique that uses a cloth (screen) with a certain level of pores and is usually made of Nylon or Silk. After that, this screen is given an image according to the designer's wishes, previously designed on HVS or tracing paper. This fabric is firmly attached to a rectangular piece of wood to produce a flat and neat screen and printout. After Jurnal Infotel, Vol. 15, No. 2, May 2023 https://doi.org/10.20895/infotel.v15i2.934 Implementation of multiple linear regression to estimate profit on sales of screen printing equipment being given photo resistance and irradiating, it must be slowly and carefully watered so that the pattern is visible, and then parts that the ink can pass through according to the picture made earlier. The process is by pouring ink on the screen's surface, and after, it is smeared using a board or rack made of rubber. One screen can only be used to make one color, while making color variants in one design requires a unique tool for precision.
Traditional marketing strategies are no longer practical to implement because the process requires more costs and time to disseminate much longer information [2]. In this modern era, many advanced technologies can shift traditional marketing into modern marketing, namely by turning into a marketing model by utilizing digital media. Digital media such as blogs, Instagram, Facebook, and so on have proliferated. Entrepreneurs can upload photos of screen-printing designs, price lists, and produced works that attract customers' interest.

II. RESEARCH METHOD
This section discusses data mining and multiple linear regression.

A. Data Mining
The terms data mining and knowledge discovery in databases are often used interchangeably to describe the process of extracting information still hidden in a large database [3]- [5]. One of the stages in the whole KDD process is Data Mining [6], [7]. In the data mining process, which is usually called knowledge discovery in databases. Knowledge discovery in databases is the application of scientific methods to a data mining [8], [9].
Data mining is a step to finding interesting patterns and knowledge from large amounts of data [7], [10]. Data mining is a search and analysis of large amounts of data and aims to find the meaning of patterns and rules. Data mining is a step of extracting or extracting data that was unknown before but can be understood and valuable from large databases [8], [11]. It is used to make essential business decisions [12], [13]. From the three responses from the experts above, an outline can be drawn; data mining is a step to find and analyze a data collection (database) in order to find an interesting pattern in order to extract information and knowledge accurately and potentially [11], [14], [15].

B. Multiple Linear Regression
Multiple linear regression method is a technique in analyzing data by trying and looking for a relationship between two or more variables [16], [17], especially between variables that contain cause and effect [18]- [20]. Multiple Linear Regression Analysis is often used as a preference analysis to determine the effect of one variable or variable with other variables [21]- [23].The general formula used in regression analysis is written in (1) [24]- [26].
where Y is a dependent variable, X is a independent variable, a is a constant variable, and b is a linear regression disrection coefficient.
To forecast the influence of a predictor variable on a criterion variable or to demonstrate the presence or absence of a functional connection between an independent variable (X) and a dependent variable.
The multiple linear regression model is a model that describes and explains the relationship of one dependent variable to two or more predictor variables [23], [26], [27]. Multiple linear regression is an extension of simple linear regression. The expansion can be seen from the number of independent variables in the regression model [18], [28]- [30]. The general form of multiple linear regression can be stated statistically as stated in (2) [31].
where Y is bound variable, X is independent variable, a, b1, b2, bn are regression parameters/regression coefficient.

III. RESULT
The research methodology is a process or scientific method. In the first stage, an analysis of the problem of estimating profits from the sale of screen printing equipment is carried out. The next stage is to collect data related to sales and the equipment sold. Then apply calculations with multiple linear regression analysis to obtain the estimated profit obtained. The following are the variables used as benchmarks in estimating sales results. It can be seen in Table 1 related to the variable data used.  The steps in this research are analyzing the problem of estimating profits from printing equipment sales, then collecting data from sales, inventory to sales profits each month, after that calculations will be carried out with multiple linear regression implementation, and after that get the results of this research.
This data collection was carried out to obtain data related to direct review of the sales results of the screen-printing equipment each month. The following is sales revenue data for equipment which can be seen in Table 2.
It takes an algorithm that will be used as a step in an analysis in processing and solving a problem. Fig. 2 is a flowchart or flow of problem solving using the Multiple Linear Regression method in this study.

A. Calculate the Value of the Coeffecient of Multipple Linear Regression
The regression coefficient is vital in analyzing regression. The benefit of the regression coefficient is to form a model of the regression equation on a problem under study. Calculating the regression coefficient can be done by calculating the mathematical equation from the equation formula pattern that has been determined in the provisions of multiple linear regression. As can be seen in Table 3 below about the regression coefficient.

V. CONCLUSION
Based on the analysis of the problems that occur in the research on estimating the sale of screen printing tools using the multiple linear regression method as a type of statistical analysis, to predict the value of the dependent variable when the independent variables have a known value, the following conclusions can be drawn: Cost of Goods, Selling Price, Total Expenses, and Total Sales are used as variables that affect Total Sales, which will then be calculated for Estimation. Based on the calculation, the selling value of the Cahaya Sablon store is Rp. 215,494,292.