The historical daily demand for an item is 79. The CEO decides to invest in a
marketing campaign to increase sales. After the campaign the manager observes a new monthly demand of 97. In both cases the sample size is 36. The CEO wants to know if the marketing campaign was successful with a 90% confidence. Assume that monthly sales follow a normal distribution and that the standard deviation is 21.
1. What kind of hypothesis test the business analyst should apply to answer the CEO question?
2. Formulate the null and the alternative hypothesis.
3. Answer the CEO question. Did the marketing campaign increase sales with a confidence of 90%? You can use Excel or SAS to answer this exercise.