GBA334 homework

23.Enrollment in a particular class for the last four semesters has been 115, 120, 110, and 130. Suppose a

one-semester moving average was used to forecast enrollment (this is sometimes referred to as a naïve

forecast). Thus, the forecast for the second semester would be 115, for the third semester it would be 120,

and for the last semester it would be 110. What would the MSE be for this situation?

A) 196.00

B) 230.67

C) 175.00

D) 11.60

E) None of the above

27. Sales for boxes of Girl Scout cookies over a 4-month period were forecasted as follows: 100, 120, 115, and

123. The actual results over the 4-month period were as follows: 110, 114, 119, 115. What was the MAD of the

4-month forecast?

A) 0

B) 5

C) 7

D) 108

E) None of the above

33.

The diagram below illustrates data with a

A) negative correlation coefficient.

B) zero correlation coefficient.

C) positive correlation coefficient.

D) correlation coefficient equal to +1.

E) None of the above

36. A prediction equation for the number of people (in 1,000s) and the annual waste total (in metric tons) was performed using simple linear regression. In the regression printout shown below, what can be said about thelevel of significance for the overall model?

SUMMARY OUTPUT

Regression Statistics

Multiple R 0.715257514

R Square 0.511593311

Adjusted R Square 0.496330602

Standard Error 50.43909112

Observations 34

ANOVA

df SS MS F Significance F

Regression 1 85276.17996 85276.17996 33.51917 1.99773E-06

Residual 32 81411.26122 2544.101913

Total 33 166687.4412

Coefficients Standard Error t Stat P-value Lower 95%

Intercept 612.3757625 43.18367091 14.18072502 2.39E-15 524.4135038

# People 1.128638579 0.194943283 5.789574096 2E-06 0.731552108

????????????????????????

????????????????????????

A) Population size is not a good predictor for the amount of waste.

B) The significance level for the intercept indicates the model is not valid.

C) The significance level for population indicates the slope is equal to zero.

D) The significance level for population indicates the slope is not equal to zero.

E) None of the above

41. Describe the purpose and structure of a scatter diagram. (Points : 4)

45. Demand for a particular type of battery fluctuates from one week to the next. A study of the last six

weeks provides the following demands (in dozens): 4, 5, 3, 2, 8, 10 (last week).

Forecast demand for the next week using a two-week moving average. (Round to nearest hundredth

4

46. Demand for a particular type of battery fluctuates from one week to the next. A study of the last six

weeks provides the following demands (in dozens): 4, 5, 3, 2, 8, 10 (last week).

Forecast demand for the next week using a three-week moving average. (Round to nearest hundredth)

47. Use simple exponential smoothing with ? = 0.3 to forecast battery sales for February through May. Assume that the forecast for January was for 22 batteries.

Month Automobile Battery Sales Forecasted Battery Sales

January42 -------

February 33

March 28

April 59

48.

The following table represents the number of applicants at popular private college in the last four years.

Month New members

2007 10,067

2008 10,940

2009 11,116

2010 10,999

Assuming ? = 0.2, ? = 0.3, an initial forecast of 10,000 for 2007, and an initial trend adjustment of 0 for 2007,use exponential smoothing with trend adjustment to come up with a forecast for 2011 on the number of applicants.

Forecast for 2011 = __________ (Fill in the blank with correct answer)

49.

Using the diagram below. The predicted demand of 2014 using the regression model is (Round answer to nearest whole number)

50.

George Crowder is conducting research on monthly expenses for a waste management company. His dependent variable is annual waste in metric tons while his independent variable is number of people (in thousands) that live in 25 selected cities. Below is his Excel output.

A) What is the prediction equation for the annual metric tons of waste based on the population?

B) Based on his model, each additional (1000) increase in people the predicted waste in metric tons is increased by how much?

C) Based on the significance F-test, is this model a good prediction equation?

D) What percent of the variation in waste is explained by the size of the population?

E) Can the null hypothesis that the slope is zero be rejected? Why or why not?

F) What is the value of the correlation coefficient and what conclusions can you draw about the model based on the correlation coefficient.