(iv) Test whether there is a difference in sales between stores with different advertising strategies at 5% significance level. Explain the steps that should be taken to ensure that the discrepancy in...

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Extracted text: (iv) Test whether there is a difference in sales between stores with different advertising strategies at 5% significance level. Explain the steps that should be taken to ensure that the discrepancy in sales is influenced by the advertising strategy only and no other factors such as location, population density, etc. (v) F 9,005 = 4.2565; F11.005 =3.9823; F ,005 = 3.8625; F, 12.005 = 3.49


Extracted text: The management of a chain grocery store wanted to compare the effect of three different types of advertising strategy on mean sales of its chain store. In order to conduct the study, 12 chain stores were randomly selected and divided into three groups of four stores. Strategy 1 was used in four stores, strategy 2 in four others, and strategy 3 in the remaining four stores. The allocation of strategy to stores was made randomly. The amount of sales (in RM 000's) during a month at each of the twelve stores were recorded. It is known that the monthly sales in all stores are approximately normally distributed. The table shown below reports the sales information. Strategy III (prizes for purchases above certain amount) Strategy I (Voucher) Strategy II (Discounts) Observation 1 96 135 160 Observation 2 129 131 150 Observation 3 135 129 148 Observation 4 115 120 127 Mean 118.75 128.75 146.25 Standard 17.3277 6.3443 13.8654 Deviation Source of Variation Treatment Total SS 1550 3148.25 (i) Obtain 95% confidence interval of difference between the mean sales for the month in stores with display type II and display type III. (i1) Based on the value calculated in part (i), determine if the difference in the mean sales is statistically significant. (111) Test the claim that the standard deviation of sales between stores with the strategy I and II are the same at 5% significance level.