STA2020F 2006 TEST 3

STA2020F 2006 TEST 3 - STA2020F Class Test 3 Date: 24 th...

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Unformatted text preview: STA2020F Class Test 3 Date: 24 th May 2006 Time: 1 hour 30 minutes Total marks: 50 Instructions: Answer all the questions in your blue answer book. A formula sheet and the relevant statistical tables are provided at the end of this test paper. Negative marking in effect. Mark of -0.5 for every wrong answer, 0 for no answer and 2 marks for a correct answer. The next 6 questions refer to the following problem setting: The following data refers to the monthly sales of Jackets (in R1 000) for a particular clothing store. Jan-04 45 Jan-05 46 Feb-04 42 Feb-05 41 Mar-04 43 Mar-05 43 Apr-04 44 Apr-05 47 May-04 50 May-05 51 Jun-04 56 Jun-05 56 Jul-04 64 Jul-05 67 Aug-04 60 Aug-05 62 Sep-04 58 Sep-05 61 Oct-04 53 Oct-05 50 Nov-04 49 Nov-05 49 Dec-04 47 Dec-05 46 To test if there was trend in the series a monthly regression was performed with time being the independent variable (where t=1 for Jan-04). The resulting model was outputted: Y-hat = 48.02 + 0.26t The standard error of the time co-efficient was given as 0.11. 1) If you were to model the time series using the components of a time series, which components would you expect to find? a) Error only b) Trend only c) Trend, Seasonality and error only d) Trend and Seasonality only e) Seasonality and error only 2) Which of the following is the correct value for the MA(6) smoothed average for Nov-04 ? a) 50.25 b) 49 c) Not possible to calculate d) 50.58 e) 60.33 3) It was decided to forecast the sales of jackets. Which of the following is the MA(3) forecast for Jan-06? a) 50 b) 46 c) 49.666 d) 48.33 e) 45.5 4) Which of the following is the exponential smoothed forecast (w = 0.3) for Apr-04? a) 45.33 b) 43.77 c) 30.87 d) 43.54 e) 43.12 5) Which of the following is true with regard to trend in the series? a) There is insignificant trend at the 10% level b) There is a trend, as the coefficient of time is positive indicating a time trend c) There is a significant trend at the 5% level d) 0.26<1.318, therefore there is a significant trend e) Not possible to tell from the information given 6) If the seasonal index for Jan-March is 0.866, which of the following is the value for the Trend Equation with Seasonal index forecast for Jan-06? a) 42.02 b) 47.21 c) 62.67 d) 54.52 e) 54.27 The next 2 questions relate to the following problem setting: The following data represents the value (in thousands of Rands) of computers sold by The Computer Shop over the two year time period Jan-04 to Dec-05. Jan-04 17 090 Jan-05 18 645 Feb-04 16 195 Feb-05 18 700 Mar-04 16 413 Mar-05 19 563 Apr-04 15 335 Apr-05 19 962 May-04 18 863 May-05 21 287 Jun-04 18 219 Jun-05 21 036 Jul-04 19 344 Jul-05 22 391 Aug-04 19 259 Aug-05 22 847 Sep-04 19 712 Sep-05 22 690 Oct-04 19 413 Oct-05 22 440 Nov-04 20 144 Nov-05 23 733 Dec-04 20 319 Dec-05 22 161 Some statisticians suspected that there might have been a seasonality component in the number of computers sold over this time period. A monthly regression was run on time and the following output was obtained: Y-hat = 16226 + 287.75t run on time and the following output was obtained: Y-hat = 16226 + 287....
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This note was uploaded on 04/06/2010 for the course ECON 2342 taught by Professor James during the Three '09 term at ADFA.

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STA2020F 2006 TEST 3 - STA2020F Class Test 3 Date: 24 th...

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