Develop a multiple regression model for predictingcurrent salary as a function of the othervariables.

Read pages 233-257 paying special attention to:Modeling relationships and trends in DataExample 8.1, 8.2, 7 8.3 Simple Linear RegressionMultiple Linear regression paying special attention to the Analytics in Practice on page 253. Complete exercises 3, 4, 15, 16, 18, and the Performance Lawn Equipment Case on page 272. post your work for review and grading.Exercises3. Using the data in the Excel file Demographics, determineif a linear relationship exists between unemploymentrates and the cost of living indexes byconstructing a scatter chart. Visually, do there appearto be any outliers? If so, delete them and then find the best-fitting linear regression line using the ExcelTrendline tool. What would you conclude about thestrength of any relationship? Would you use regressionto make predictions of the unemployment ratebased on the cost of living?Exercises4. Using the data in the Excel file Weddings constructscatter charts to determine whether any linear relationshipappears to exist between (1) the weddingcost and attendance, (2) the wedding cost and thevalue rating, and (3) the couple’s income and weddingcost only for the weddings paid for by the brideand groom. Then find the best-fitting linear regressionlines using the Excel Trendline tool for each ofthese charts.Exercises15. The Excel file Concert Sales provides data on salesdollars and the number of radio, TV, and newspaperads promoting the concerts for a group of cities. Developsimple linear regression models for predictingsales as a function of the number of each type of ad.Compare these results to a multiple linear regressionmodel using both independent variables. Examinethe residuals of the best model for regression assumptionsand possible outliers.Exercises16. Using the data in the Excel file Home Market Value,develop a multiple linear regression model for estimatingthe market value as a function of both the ageand the size of the house. Predict the value of a housethat is 30 years old and has 1,800 square feet, andone that is 5 years old and has 2,800 square feet.Exercises18. The Excel file Salary Data provides information oncurrent salary, beginning salary, previous experience(in months) when hired, and total years of educationfor a sample of 100 employees in a firm.a. Develop a multiple regression model for predictingcurrent salary as a function of the othervariables.b. Find the best model for predicting the current salaryusing the t-value criterion.ProblemPerformance Lawn Equipment Case, (Page 272).In reviewing the PLE data, Elizabeth Burke noticed thatdefects received from suppliers have decreased (worksheetDefectsAfter Delivery). Upon investigation, she learnedthat in 2010, PLE experienced some quality problemsdue to an increasing number of defects in materialsreceived from suppliers. The company instituted an initiativein August2011 to work with suppliers to reducethese defects, to more closely coordinate deliveries, and toimprovematerials quality through reengineering supplierproduction policies. Elizabeth noted that the program appearedto reverse an increasing trend in defects; she wouldlike to predict what might have happened had the supplierinitiative not been implemented and how the number ofdefects might further be reduced in the near future.In meeting with PLE’s human resources director,Elizabeth also discovered a concern about the high rateof turnover in its field service staff. Senior managers havesuggested that the department look closer at its recruitingpolicies, particularly to try to identify the characteristicsof individuals that lead to greater retention. However, ina recent staff meeting, HR managers could not agree onthese characteristics. Some argued that years of educationand grade point averages were good predictors. Othersargued that hiring more mature applicants would lead togreater retention. To study these factors, the staff agreedto conduct a statistical study to determine the effect thatyears of education, college grade point average, and agewhen hired have on retention. A sample of 40 field serviceengineers hired 10 years ago was selected to determinethe influence of these variables on how long each individualstayed with the company. Data are compiled in theEmployee Retention worksheet.Finally, as part of its efforts to remain competitive,PLE tries to keep up with the latest in production technology.This is especially important in the highly competitivelawn-mower line, where competitors can gain a realadvantage if they develop more cost-effective means ofproduction. The lawn-mower division therefore spends agreat deal of effort in testing new technology. When newproduction technology is introduced, firms often experiencelearning, resulting in a gradual decrease in the timerequired to produce successive units. Generally, the rate ofimprovement declines until the production time levels off.One example is the production of a new design for lawnmowerengines.