Question

The data is for weekly sales in the dry goods department at the Methuen Wal*Mart store in fiscal 2002-2003. Peak values, i.e. spikes, usually occur at holiday periods. Week 1 is the first week of February 2002. Dollar values are adjusted in order to disguise true sales figures, but trends in the data are retained for analysis purposes.

Week(x)	Sales in $(y)	Week(x)	Sales in $(y)
26	15200	52	22400
27	15600	53	20900
28	16400	54	18800
29	15600	55	22400
30	14200	56	19400
31	14400	57	20000
32	16400	58	18100
33	15200	59	18000
34	14400	60	19600
35	13700	61	19000
36	15000	62	19200
37	14100	63	18000
38	14400	64	17600
39	14000	65	17200
40	15600	66	19800

Generate supporting Excel graphs (use scatter plots with straight lines) to answer the following questions for the Dry Goods 2002-2003 data.

1. Identify at least 6 holiday periods or special events that cause spikes in the data.
   1. In each case, give the week number, date and what holiday or special event it represents.  
   2. Which holiday results in the maximum sales for this department and how much are the sales?  

2. Model the data
   1. Make two different linear models for the dat Each should be generated from a pair of data points. (Do not use an Excel trend line or least squares regression line.) For each linear model, find the equation of the line. Show your work. Write the equation in slope-intercept form.  

2. Run statistical procedure of Excel to generate the least squares linear regression model for the data. (Refer to “Finding the Equation of the Line or ..” in Appendix B on page 691) Write the equation in slope-intercept form.

3. For each of the three linear models you’ve found in 2a and 2b, discuss the meaning of their specific slope and y-intercept (not copy the general definition.) Also provide an analysis as to why you like or dislike that particular model. Discuss the rationale behind the model that you believe best predicts future results.

3. Predict and analyze sales for the next four weeks.
   1. Using the best model, predict sales for the next four weeks. Show your calculations.  
   2. Using these predicted values, compute the percent rate of increase for the next four weeks.  

4. If you were the manager of this department, what recommendations would you make to the person in charge of ordering inventory?  

Answer 1