1. The mathematical model for making decision to sell the rubber latex to reach the highest return in economics Researchers Raviwan Akarapatima Subongkoch Subhadhirasakun Montira Tangsangasaksri Advisor Mr. Sorachai Saelim Mrs. Suphannee Nawasitpaisan

2. Introduction

3. Introduction

4. Objective This project attempts to develop mathematical model in order to help make decisions among selling rubber latex, raw rubber sheet, and rubber scraps with maximum revenue.

6. 1. Producing a rubber sheet Prepare formic acid’s concentration Find Dry Rubber Content (DRC) Find Total Solid Content (TSC) Produce a rubber sheet

7. Finding Dry Rubber Content (DRC) Spin the rubber latex in order to remove an ammonia Pipette rubber latex 20 mL, weight Drop Formic acid 90% w/v, wait until it hard Weight and find % DRC Wash out the acid and bake at 60 0 C for 6 hours

8. (Total Solid Content; TSC) Finding Total Solid Content (TSC) Spin the rubber latex in order to remove an ammonia Pipette rubber latex 20 mL, weight Weight and find % DRC Bake at 60 0 C for 6 hours

9. Producing a rubber sheet Mix rubber latex 6 mL and water 4 mL together in the vessel Pipette Formic acid 1.50% 0.78 mL into the vessel wait until it hard for 30 minutes

10. Wash hard rubber, weight, observe and note a result Bake the rubber at 60 ° C Do all experiments again, change formic acid’s concentration 1.50%, 1.75%, 2.00%, 2.25%, 2.50%, 2.75% and 3.00% respectively Producing a rubber sheet

11. 2. Making a questionnaires Part 1 Individual information such as sex, age, etc. Part 2 The level of contentment of selling raw rubber sheet, rubber latex and rubber scraps test Part 2.1 Evaluate from generality Part 2.2 Evaluate from some conditions

12. Part of the Questionnaire

13. Part of the Questionnaire

14. Part of the Questionnaire

15. 3. Analyze data from the questionnaire Analyze frequencies from the questionnaire Create Regression equation

16. Creating Regression Equations Analyze data with Regressing from SPSS program Make and test Hypothesis Find the coefficients of each variable Create Regression Equations

18. Finding the coefficients of each variable Use Coefficients table from SPSS program

19. Creating Regression Equations Find y intercept

20. Put the coefficients in front of x n Make an equations like = a+a 1 x 1 +a 2 x 2 +a 3 x 3 +…+a n x n Creating Regression Equations

21. 4. Analyze the level of contentment Analyze the mean of each item of the questionnaire Substitute x with mean in the equations Compare the level of contentment in chart form

22. Results Table 1 Dry Rubber Content (DRC ) 41.673  4.164 7.530  0.849 18.067  0.097 After baked Before baked DRC (%) Weight (g)

23. Results Table 2 Total Solid Content (TSC) 41.777  0.728 7.570  0.070 18.123  0.324 After baked Before baked TRC (%) Weight (g)

24. Results 2.00 % 1.75 % 1.50 % Producing rubber sheet

25. 2.50 % 2.75 % 2.25 % 3.00 % Results

26. Results 1. Let the producing time be constant.

27. 1. Let the producing time be constant. a is convenience. From the equation b is price. c is payment. d is quality of product. e is asset. f is amount of Para latex.

28. Results 2. Let the price of selling product be constant.

29. 2. Let the price of selling product be constant. a is convenience. From the equation b is time of production. c is payment. d is quality of product. e is asset. f is amount of Para latex.

30. Results 3. Let the convenience of product transportation be constant.

31. 3. Let the convenience of product transportation be constant. a is price. From the equation b is time of production. c is payment. d is quality of product. e is asset. f is amount of Para latex.

32. Results 4. Let the occupational factors are the same.

33. 4. Let the occupational factors are the same. a is convenience. From the equation b is price. c is time of production . e is quality of product. f is asset. g is amount of Para latex. d is payment.

34. Results 5. Let a number of garden are constant.

35. 5. Let a number of garden are constant. a is convenience. From the equation b is price. c is time of production . e is quality of product. f is asset. g is amount of Para latex. d is payment.

36. Results 6.1 Let Para latex in rainy season is constant.

37. 6.1 Let Para latex in rainy season is constant. a is price. From the equation b is convenience. c is investment. d is amount of Para latex. e is production. f is that It’s not an optional to sell other products.

38. Results 6.2 Let Para latex in winter is constant.

39. 6.2 Let Para latex in winter is constant. a is price. From the equation b is convenience. c is investment. d is amount of Para latex. e is production. f is that It’s not an optional to sell other products.

40. Results 6.3 Let Para latex in summer is constant.

41. 6.3 Let Para latex in summer is constant. a is price. From the equation b is convenience. c is investment. d is amount of Para latex. e is production. f is that It’s not an optional to sell other products.

42. Analyzed Data 1. Let the producing time be constant.

43. Analyzed Data 2. Let the price of selling product be constant.

44. Analyzed Data 3. Let the convenience of product transportation be constant.

45. Analyzed Data 4. Let the occupational factors are the same.

46. Analyzed Data 5. Let a number of garden are constant.

47. Analyzed Data 6.1 Let Para latex in rainy season is constant.

48. Analyzed Data 6.2 Let Para latex in winter is constant.

49. Analyzed Data 6.3 Let Para latex in summer is constant.

51. Suggestion From the column charts of satisfaction, mostly of the gardeners of sample group are satisfy to sell “ rubber sheets ” .

52. Suggestion These sets of equation can be apply in many places that have been planted Para trees ,but the equations may be chanced because their satisfactions are different. (The way to make the equations are follow in above.)

54. References กัลยา วานิชย์บัญชา . การใช้ SPSS for Windows ในการวิเคราะห์ข้อมูล . พิมพ์ครั้งที่ 5. กรุงเทพฯ : โรงพิมพ์ ห้างหุ้นส่วนจำกัด ซี เค แอนด์ เอส โฟโต้สตูดิโอ , 2545 ต้นยางพารา [Online]. Available HTTP: http://www.forest.go.th/Private/best44.htm . ธานินทร์ ศิลป์จารุ . การวิจัยและวิเคราะห์ข้อมูลทางสถิติด้วย SPSS . พิมพ์ครั้งที่ 4. กรุงเทพฯ : บริษัทวี . อินเตอร์ พริ้นท์ , 2548. ศิริชัย พงษ์วิชัย . การวิเคราะห์ข้อมูลทางสถิติด้วยคอมพิวเตอร์ . พิมพ์ครั้งที่ 15. กรุงเทพฯ : โรงพิมพ์แห่งจุฬาลงกรณ์มหาวิทยาลัย , 2548. สวนยางพารา [Online]. Available HTTP: http://chaosuan.com/modules.php?op= เสาวนีย์ ก่อวุฒิกุลรังษี . 2547. การผลิตยางธรรมชาติ . คณะวิทยาศาสตร์และเทคโนโลยี ภาควิชาเทคโนโลยียางและพอลิเมอร์ มหาวิทยาลัยสงขลานครินทร์