# Stats

**Topics:**Normal distribution, Statistics, Standard deviation

**Pages:**4 (847 words)

**Published:**December 4, 2012

1. Suppose a researcher wants to design a new study with a power of 0.8 and a significance of 0.05 to test whether the caffeine content for a brand of coffee is really 100mg. A previous study gave a mean caffeine level for this brand of 110 mg and a standard deviation of 7 mg. Use PROC POWER to determine how many cups of coffee need testing.

2. A company did a study to estimate the effect of different promotional strategies on the market share of one of their products. Over a period of 36 months they varied their promotional strategy. There are four strategies: Ordinary (standard pricing and advertising); Discount (price discount with standard advertising); Promotion (standard pricing, enhanced advertising); and Both (price discount with enhanced advertising). Each month one of the strategies was employed and the market share (the percentage of purchasers of the given product type that selected the company's product). Higher market share is better for the company. The table below records the number of months in which each strategy was used (n) and a summary of the market share results in those months.

|Strategy |Pricing |Advertising |n |mean |SD | |Ordinary |standard |standard |8 |2.40 |0.12 | |Discount |Discount |standard |7 |2.42 |0.11 | |Promotion |Standard |enhanced |8 |2.74 |0.18 | |Both |Discount |enhanced |13 |2.90 |0.18 |

a. What is the factor for this experiment and its levels?

b. Suppose that a one-way ANOVA for the effect of strategy on market...

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