Page 234 - DMGT404 RESEARCH_METHODOLOGY

Research Methodology

Notes 3. What are the normal equations of parabola fit?
4. Determine the seasonal indices from the following data by the method of link relatives:
Year I Qtr II Qtr III Qtr IV Qtr

2000 42 44 40 38
2001 36 38 36 34
2002 48 50 48 40
2003 38 42 40 38

5. Find seasonal variations by the ratio to trend method, from the following data:

Year I Qtr II Qtr III Qtr IV Qtr
2000 40 44 42 40
2001 36 40 38 36
2002 48 52 46 42
2003 38 42 40 38

6. Assuming that trend and cyclical variations are absent, compute the seasonal index for
each month of the following data of sales (in ‘000) of a company:

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2001 38 36 36 38 34 34 32 30 32 34 32 32

2002 34 32 32 32 30 34 30 32 30 34 30 34
2003 32 30 30 34 32 32 34 34 32 36 34 36

7. Why does minimizing the MSE remain a key criterion in selection estimators?
8. How would you estimate the scale parameter of distributions for which the variance and
standard deviation do not exist?
9. What will be the effect on the moving averages if the trend is non-linear?

10. “Secular trend is that irreversible movement which continues, in general, in the same
direction for a considerable period of time.” Comment.
11. Fit a trend line to the following data by method of semi average and forecast the sales for
2007.
Year Sales of the company in thousands of units
2000 105
2001 106
2002 116
2003 120
2004 114
2005 128
2006 134

12. Using the 3 yearly moving averages, determine the trend values and also the short-term
error.

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