You work for a firm that has invested heavily in an advertising campaign to increase sales at its stores this year, and you are tasked with evaluating whether to continue the campaign. In previous years, sales growth has averaged 5% per year across its 42 stores, with a standard deviation of 1.8%. This year, sales increased by 5.5% on average in those 42 stores.

Your manager wants to continue the campaign only if it was effective in increasing sales growth. Would you recommend continuing the campaign (use 95% confidence and a p-value test)?

For the answer, please define the null and alternative hypothesis, state the significance level, compute value of test statistic, find critical value/p-value, and decide whether we reject/accept it.

Thank you very much! I will upvote immediately.