Exam 9: Forecasting

A counseling service records the number of calls to their hotline for the last year. Plot the data and determine which forecasting technique would be best among a moving average, weighted moving average, exponential smoothing, and regression line. Month Demand Tanuary 111 February 127 March 146 April 159 May 165 Tune 165 July 178 August 182 September 191 October 208 November 223 December 228

A poultry farmer that dabbles in statistics is interested in exploring the relationship between layer pellets and the output of his laying hens. For ten days he records the number of ounces of layer pellets and the number of eggs that are produced. What is his regression equation based on the data? Layer Pellets Eggs 29 24 27 22 22 20 21 20 23 22 28 23 22 21 28 22 22 20 29 24

As yet another earthquake rattled his china cabinet, the data scientist vowed to once and for all determine whether hydraulic fracturing (or fracking)was predictive of the number of earthquakes in the region. What is the regression equation based on the data? Injections Earthquakes 137 682 331 833 360 905 442 1008 478 1482 529 1742

A seasonal index less than 1.0 means that the model is overforecasted.

A company keeps track of unit sales and notes a strong trend during the past eight periods. They use an adjusted exponential smoothing model with an alpha equal to 0.7 and a beta equal to 0.6. Using the demand data and previous forecasts shown in the table, develop a forecast for period 4. Week \# Units Unadjusted Forecast Trend Adjusted Forecast 1 68 65.0 0.0 65.0 2 72 67.1 1.3 68.4 3 80 4 93 5 108 6 121 7 125 8 139

Describe three qualitative forecasting techniques and compare their strengths and weaknesses.

The panel consensus forecasting approach requires that the forecasting team discuss their forecast as a team but the ________ requires that each member of the team develop a separate forecast initially.

A drive-in restaurant has experienced the following customer loads on the past 8 Friday nights. If their forecast for period 7 was 59 customers, then what is their forecast for period number 8 using a smoothing constant of 0.7? Friday \# Customers 1 49 2 55 3 57 4 59 5 56 6 61 7 62 8 63

Two smoothing models that yield identical forecasts are exponential smoothing with an alpha equal to ________ and a moving average with n equal to ________.

A qualitative forecasting technique well-suited for demand forecasts of a new product or service is the:

Examine these two graphs and based on the demand pattern and axis scaling, recommend a forecasting technique (and the required parameters)that would work best for each one. Justify your recommendations.

As yet another earthquake rattled her china cabinet, the data scientist decided to test whether hydraulic fracturing (or fracking)truly was predictive of the number of earthquakes in the region. What proportion of the number of earthquakes is predicted by the number of water injections based on the available data? Injections Earthquakes 137 682 331 833 360 905 442 1008 478 1482 529 1742

A well-educated lumberjack decides to use linear regression to predict the demand for firewood based on the ambient temperature. He has collected data on firewood sales and temperature for the last several days and has performed some preliminary calculations as shown in the table. What is his regression equation based on the data? Temp Ricks Temp Squared Temp *\# Ricks 33 17 1089 561 19 32 361 608 34 20 1156 680 34 18 1156 612 20 33 400 660 24 30 576 720 17 34 289 578 30 25 900 750 38 16 1444 608 23 29 529 667 Sums 272 254 7900 6444

Multiple regression was used to forecast success in college (GPA)based upon SAT score, high school GPA, and hours spent on-line. Use the regression output shown and comment on the overall fit of the model, the usefulness of each independent variable, and the value to an admissions department of using the model to make admission decisions. What is the model's forecast for an applicant having a high school GPA of 2.5 and an SAT score of 1000 that spends 20 hours a week on-line? What other variables do you feel would make good indicators of college GPA? Regression Statistics Multiple R 0.718 R Square 0.516 Adjusted R Square 0.273 Standard Error 0.339 Observations 10 ANOVA df SS M S F Significance F Regression 3 0.735 0.245 2.128 0.198 Residual 6 0.690 0.115 Total 9 1.425 Coefficients Standard Error Stat P-value Intercept 0.541 1.262 0.43 0.68 HS GPA 0.423 0.307 1.38 0.22 SAT 0.001 0.001 1.51 0.18 On-Line 0.010 0.017 0.61 0.57

The greater the randomness in the model, the greater the number of periods that should be used in a moving average forecast.

Consider the data that generate this plot covering time for months numbered 1 to 50. What characteristic is most prominent in the pattern?

A counseling service records the number of calls to their hotline for the last year. Based on MAD, which of these models does the best job of forecasting? Month Demand Tanuary 111 February 127 March 146 April 159 May 165 Tune 165 Tuly 178 August 182 September 191 October 208 November 223 December 228

What patterns are common in time series data? Describe each one and draw one plot that displays all of these patterns. Label the patterns on your plot.

Which of these forecasts is the BEST?

The ________ value for a regression or multiple regression model shows the percentage of variability in the dependent variable that is explained by the independent variable(s).